Which makes up an ecosystem?
A. A community of organisms and nonliving factors in their habitats
B. Several species of organisms that are similar in appearance
C. A group of species and the plants that they interact with
D. Multiple populations of animals and the plants in their environment

Answers

Answer 1
A. Makes up an ecosystem

Related Questions

Help! It’s for chemistry I attached a picture thank you!

Answers

Answer:

0.15 L

Explanation:

You need to first find the volume of the container.  You can do this by dividing the mass by the density.  This will give you the mass in mL.

5.00 kg = 5,000 g

(5,000 g)/(1.00 g/mL) = 5,000 mL

5,000 mL = 5 L

Now, find the volume the seawater will take up.

(5,000 g)(1.03 g/mL) = 4854.4 mL

4854.4 mL = 4.85 L

Subtract the two volumes to find the volume that left unfilled.

5 L - 4.85 L = 0.15 L


interpretacao gerais das praticas
sobre densidade de amostra solido e liquido

Answers

Answer:

O sólido tem densidade mais alta em comparação ao líquido.

Explicação:

A densidade da amostra sólida é maior do que a densidade do líquido porque há pouco espaço entre as partículas do sólido. A densidade tem relação inversa com o volume de uma substância, se uma substância ocupa mais espaço então sua densidade é menor, enquanto se a substância ocupa menos espaço então tem maior densidade. As substâncias sólidas ocupam menos espaço em comparação com as substâncias líquidas, então podemos dizer que a densidade do sólido é maior do que as substâncias líquidas.

g A sample of unknown gas has a mass of 1.95 g and occupies 3.00 L at 1.25 atm and 20 C. What is the molar mass of the unknown gas

Answers

Answer:

Molar mass = 12.51 g/mol

Explanation:

V = 3L

P = 1.25 atm

T = 20 C = 20 + 273 = 293 K (Upon conversion to kelvin temperature)

n =?

m = 1.95g

Molar mass = ?

The variables are related by the follwing equation;

pV = nRT

where r = gas constant = 0.0821 L atm K−1

Solving for n, we have;

n = pV / RT

n = (1.25 * 3 ) / (0.0821 * 293)

n = 3.75 / 24.0553 = 0.1559 mol

The relationship between number of moles, n and molar mass is given as;

n = mass / molar mass

Molar mass = Mass / n = 1.95 / 0.1559

Molar mass = 12.51 g/mol

At what atom of the pyridine ring will oxidation and reduction reactions take place?a. 2.b. 4.c. 3.d. 1.

Answers

Answer:

1

Explanation:

Pyridine is a six membered hetrocyclic aromatic compound. Oxidation of the pyridine ring occurs at position-1.

Just like benzene, pyridine is stable towards mild oxidizing agents, however, pyridine is oxidized by peracetic acid to yield pyridine N-oxide.

If a urine sample has a mass of 244 g and a volume of 242 mL, what is its density in g/mL?

Answers

Answer:

244/242 alright

Explanation:

yesss

Answer:

244/242 or 1.00826446 g/mL

Explanation:

Density can be calculated using the following formula.

d=m/v

where m is the mass and v is the volume.

The mass is 244 grams and the volume is 242 milliliters.

m= 244 g

v= 242 mL

Substitute the values into the formula.

d= 244 g / 242 mL

Divide 244 g by 242 mL.

d= 244/242 g/mL

d= 1.00826446 g/mL

The density is 244/242 or 1.00826446 grams per milliliter.

Which sentence describes a chemical property?
A. Cars that are missing paint can rust over time.
B. A pot of water gets hotter on a burner.
O C. Paper can be cut into smaller pieces.
O D. A pitcher can hold several glasses of water.

Answers

answer is B because C and D make has nothing to do with the question and A isn’t it

Answer:

A. Cars that are missing paint can rust over time shows a chemical property of rusting.

4Fe + 3O² + 6H²O → 4Fe(OH)³.

(Iron) (Air) (Water) (Rust)

Note: The powers in equation should be written below .

Hope it helps.

1) What mass of Na2CO3 is required to make 50cc of its seminormal solution?

Answers

Answer:

[tex]m=1.325gNa_2CO_3[/tex]

Explanation:

Hello,

In this case, by considering the given seminormal solution, we infer it is a 0.5-N solution which means that we can obtain the equivalent grams as shown below for the 55 cc (0.055 L) volume:

[tex]eq-g=0.5eq-g/L*0.050L=0.025eq-g[/tex]

Next, since sodium carbonate has two sodium ions with a +1 oxidation state each, we can obtain the moles:

[tex]mol=0.025eq-gNa_2CO_3*\frac{1molNa_2CO_3}{2eq-gNa_2CO_3}\\ \\mol=0.0125molNa_2CO_3[/tex]

Finally, the mass is computed by using its molar mass (106 g/mol)

[tex]m=0.0125molNa_2CO_3*\frac{106gNa_2CO_3}{1molNa_2CO_3} \\\\m=1.325gNa_2CO_3[/tex]

Regards.

Which of the following conditions characterizes a system in a state of chemical equilibrium?
a) Reactants are being consumed at the same rate they are being produced.
b) Concentrations of reactants and products are equal.
c) Product concentrations are greater than reactant concentrations.
d) Reactant molecules no longer react with each other.
e) Rate of forward reaction has dropped to zero.

Answers

Answer:

a) Reactants are being consumed at the same rate they are being produced.

Explanation:

In a chemical reaction, chemical equilibrium is a state in which there is no change in concentration of the reactant and product. This means that as the reactants are consumed, they are also produced. Same thing with the products; immediately they are formed, they are consumed.

The option that accurately depicts a reaction at equilibrium is;

a) Reactants are being consumed at the same rate they are being produced.

150.0 grams of an isotope with a half-life of 36.0 hours is present at time zero. How long will it take
to decay to 18.75g?

Answers

Given :

Initial mass , a = 150 gm .

Half time ,

[tex]t_{\dfrac{1}{2}}=36 \ hours[/tex].

Final mass , x = 18.75 gm .

To Find :

The time taken to decay 18.75 gm .

Solution :

We know , time taken is given by :

[tex]t=\dfrac{1}{k}\times ln(\dfrac{a}{a-x})[/tex]

Here , k is a constant given by :

[tex]k=\dfrac{0.693}{t_{\dfrac{1}{2}}}\\\\\\k=\dfrac{0.693}{36}[/tex]

Putting all given value in above equation :

We get :

[tex]t=\dfrac{36}{0.693}\times ln(\dfrac{150}{150-18.75})\\\\t=6.94\ hours[/tex]

Therefore , time taken is 6.94 hours .

Hence , this is the required solution .

Fatty acids that have multiple double bonds are ?

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _

( 15 letter word )

Answers

polyunsaturated is your 15 letter word

Draw the neutral organic product expected under these reaction conditions.

Answers

Answer:

The neutral organic product is Imine.

Explanation:

From the image attached below, we will see an organic compound the question intended us to work out.

The proposed reaction is between cyclohexane and a stick structure of butylamine to yield imine as the product. The stepwise process and the mechanism carried out to get the product  of this reaction is also shown in the image attached below.

The sum of gravitational potential energy and kinetic
energy is called mechanical energy. Use Figure 2 to find the mechanical energy
of an idealized pendulum at a variety of times in its cycle. Identify any pattern you
notice in the values of mechanical energy.

Answers

Answer:

Explanation:

Mechanical energy = Gravitational potential energy + kinetic energy

Time            Gravitational potential energy        kinetic energy         Total ME

0                                    4                                                0                        4

2                                     2                                               2                        4

4                                     0                                               4                        4

6                                     2                                               2                        4

8                                     4                                               0                        4

and so on  .....

We see that total mechanical energy is always 4 which is constant .

So gravitational and kinetic energy changes cyclically but total mechanical energy is constant .

         

A chemistry teacher spends 35 minutes grading 1 students lab. They have 153 students who turn in lab papers for each lab. If the class completed 25 labs, how many minutes will the teacher spend grading lab papers? I just need to know how to set up the problem and the answer, thank you!!

Answers

Answer:

13,3875 minutes or 2,231.25 hours

Explanation:

153 x 25 = 3,825

person x lab paper = all the lab papers turned in.

35 x 3,825 = 13,3875

minutes x all the lab papers turned in = amount of minutes spent on grading

If 5.0 kJ of energy is added to a 15.5-g sample of water at 10.°C, the water is Group of answer choices

Answers

Answer:

The water is completely vaporized at this stage.

Explanation:

The complete question is

If 5.0 kJ of energy is added to a 15.5-g sample of water at 10.°C, the water is

-boiling

-completely vaporized

-frozen solid

-decomposed

-still a liquid

Energy added = 50 kJ = 50000 J

mass of water = 15.5 g = 0.0155 kg

temperature of water = 10 °C

We know that the energy posses by a mass of water at a given temperature is given as

H = mcT

where H is the energy possessed by the mass of water

m is the mass of the water

c is the specific heat capacity of water = 4200 J/ kg- °C

T is the temperature of the water

substituting values, the energy of this amount of water is

H = 0.0155 x 4200 x 10 = 651 J

If 50 kJ is added to the water, the energy increases to

50000 J + 651 J = 50651 J

Temperature of this water at this stage will be gotten from

H = mcT

we solve for the new temperature

50651 = 0.0155 x 4200 x T

50651 = 65.1 x T

T = 50651/65.1 = 778.05 °C

This temperature is well over 100 °C, which is the vaporization temperature of water, but less than 3000 °C for its molecules to decompose.

PLEASE HELP I WILL GIVE BRAINLIEST 40+ POINTS. PLEASE
This is the periodic table(image below)

Using information from the periodic table, which diagram shows a
correct model for an atom neon(also image below)

Answers

Answer:

A.

Explanation:

Neon 19 is shown on image A.

Diagram  A shows the correct model for an atom neon.

What are the properties of periodic table ?

The arrangement of elements by their periodic properties and physical and chemical characteristic make a periodic table.

The chemical and physical properties of the group of the element belongs to Alkali Metals, Less dense, One loosely bound valence electron, Highly reactive, Low ionization energy, Low electronegativity

The lanthanides and actinides are also transition metals, these are softer and nonmetallic properties, all of these elements tend to have a shiny, metallic appearance, radioisotopes of other elements, actinides are radioactive.

Learn more about periodic table, here:

https://brainly.com/question/11155928

#SPJ2

Classify each as a physical or chemical change.
Explain each answer.
a) When limestone is heated carbon dioxide and
calcium oxide result.
b) Digesting a candy bar.
c) Copper can be drawn into thin wires.
d) Ripening of fruits.
e) Ice floats on water​

Answers

Answer:

a) When limestone is heated in a kiln, the calcium carbonate breaks down into calcium oxide and carbon dioxide. This type of reaction is called thermal decomposition. The process is called calcining. ... Slaked lime is used to reduce the acidity of the soil, which helps increase its fertility.

b) Mechanical digestion occurs in the mouth, stomach, and small intestine. Food is chemically changed indigestion when new, smaller substances are formed. These chemical changes are examples of chemical digestion. Chemical digestion begins in the mouth when enzymes in saliva begin to break down carbohydrates.

c)  Copper is a ductile metal. This means that it can easily be shaped into pipes and drawn into wires. Copper pipes are lightweight because they can have thin walls. They don't corrode and they can be bent to fit around corners.

d)  Ripening of fruits is a chemical change. During ripening the pigment present in the skin of the fruit changes and this can not be reversed back. it is a chemical change as once a fruit ripens it cannot turn raw again.

e)  Ice is a unique substance because it is solid-state — ice — is less dense than its liquid state. Because of this property, ice floats in water. Physical properties are characteristics of a substance. They do not change. Physical properties include colour, smell, freezing/melting point, and density.

which variable is directly proportional to frequency?
velocity
wavelength
position
energy

Answers

Answer:

its letter D Energy I think

A student uses paper towels to clean up a small chemical spill in the lab.
Where should the dirty paper towels be placed?
A in the lab sink
B in the wastebasket
C in the chemical waste container
D in the hazardous waste container

Answers

Answer:

C. in the chemical wastebasket

C is the answer: chemical waste container

What is all matter I’m the universe made of?

Answers

Answer:

The building block that makes up all matter in the universe is atoms.

When the equation Sn + HNO₃ → SnO₂ + NO₂ + H₂O is balanced in acidic solution, what is the smallest whole-number coefficient for Sn?

Answers

Answer:

1.

Explanation:

Hello,

In this case, for the given reaction we first assign the oxidation state for each species:

[tex]Sn^0 + H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 + N^{4+}O^{2-}_2 + H^+_2O^-[/tex]

Whereas the half reactions are:

[tex]Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-\\\\H^++H^+N^{5+}O^{-2}_3 +1e^-\rightarrow N^{4+}O^{2-}_2+H_2O[/tex]

Next, we exchange the transferred electrons:

[tex]1\times(Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-)\\\\4\times (H^++H^+N^{5+}O^{-2}_3 +1e^-\rightarrow N^{4+}O^{2-}_2+H_2O)\\\\\\Sn^0+2H_2O \rightarrow Sn^{4+}O_2 +4H^++4e^-\\\\4H^++4H^+N^{5+}O^{-2}_3 +4e^-\rightarrow 4N^{4+}O^{2-}_2+4H_2O[/tex]

Afterwards, we add them to obtain:

[tex]Sn^0+2H_2O+4H^++4H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 +4H^++4N^{4+}O^{2-}_2+4H_2O[/tex]

By adding and subtracting common terms we obtain:

[tex]Sn^0+4H^+N^{5+}O^{-2}_3 \rightarrow Sn^{4+}O_2 +4N^{4+}O^{2-}_2+2H_2O[/tex]

Finally, by removing the oxidation states we have:

[tex]Sn + 4HNO_3 \rightarrow SnO_2 + 4NO_2 + 2H_2O[/tex]

Therefore, the smallest whole-number coefficient for Sn is 1.

Regards.

What is the concentration of OH− and pOH in a 0.00072 M solution of Ba(OH)2 at 25 ∘C? Assume complete dissociation.

Answers

Given :

0.00072 M solution of [tex]Ba(OH)_2[/tex] at [tex]25^oC[/tex] .

To Find :

The concentration of [tex]OH^-[/tex]and pOH .

Solution :

1 mole of [tex]Ba(OH)_2[/tex] gives 2 moles of [tex]OH^-[/tex] ions .

So , 0.00072 M mole of [tex]Ba(OH)_2[/tex] gives :

[tex][OH^-]=2 \times 0.00072\ M[/tex]

[tex][OH^-]=0.00144\ M[/tex]

[tex][OH^-]=1.44\times 10^{-3}\ M[/tex]

Now , pOH is given by :

[tex]pOH=-log[OH^-]\\\\pOH=-log[1.44\times 10^{-3}]\\\\pOH=2.84[/tex]

Hence , this is the required solution .

What is the density of an object with a volume of 30ml and a mass of 90 grams

Answers

Answer:

Density = 3 g/mL

Explanation:

Density of a substance can be found by using the formula

[tex]Density = \frac{mass}{volume} [/tex]

From the question

mass = 90 g

volume = 30 mL

Substitute the values into the above formula and solve for the Density

That's

[tex]Density = \frac{90}{30} \\ = \frac{9}{3} [/tex]

We have the final answer as

Density = 3 g/mL

Hope this helps you

Water flows over Niagara Falss at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing that the graviatational potential energy of falling water per second = mass (kg) x height (m) x gravity (9.8 m/s2), what is the power of Niagara Falls? How many 15 W LED light bulbs could it power?

Answers

Answer:

1. 176 × 10^12 W ; 78400000000

Explanation:

Given the following :

Fall rate = 2,400,000kg/s

Average height of fall = 50m

Gravitational Potential of falling water = mgh = mass × acceleration due to gravity × height =

How many 15 W LED light bulbs could it power?

Recall : power = workdone / time

Workdone = gravitational potential energy

Mass of water = density * volume

Density of water = 1 * 10^3kg/m^3

Rate of fow = volume / time = 2400000

Hence,

Power = 1000 * 2,400,000 * 9.8 * 50

Power = 1176000000000

Power = 1. 176 × 10^12 W

How many 15 W LED light bulbs could it power?

1176000000000 / 15 = 78400000000

= 78400000000 15 W bulbs

3.25 kcal is the same amount of energy as

Answers

Answer:

3.25 kcal has the same amount of energy as 13600 J

The density of mercury is 13.6 g/mL what is the density in lbs/L ( 1 lb hint =0.454 kg )

Answers

Answer:

[tex]30.0\frac{lb}{L}[/tex]

Explanation:

Hello,

In this case, since 454 g are equivalent to 1 pound and 1000 millilitres are equivalent to 1 liter, the required density is computed below by applying the corresponding conversion factor:

[tex]=13.6\frac{g}{mL} *\frac{1lb}{454g} *\frac{1000mL}{1L} \\\\=30.0\frac{lb}{L}[/tex]

Regards.

If 12.3 grams of a substance burns in air to produce 15.9 grams of a compound, what mass of the air reacted?

Answers

Answer:

[tex]m_{air}=3.6g[/tex]

Explanation:

Hello,

In this case, given the law of conservation of mass which states that mass cannot be created nor destroyed, since the produced mass of the compound is 15.9 g and the mass of the initial substance is 12.3 g we obtain the mass of air by applying the following equation:

[tex]m_{reactants}=m_{products}\\\\m_{substance}+m_{air}=m_{product}[/tex]

Thus, solving for the mass of air we obtain:

[tex]m_{air}=m_{product}-m_{substance}\\\\m_{air}=15.9g-12.3g\\\\m_{air}=3.6g[/tex]

Regards.

SpongeBob & Friends and the Scientific Method
Scenario A. Krusty Krabs Breath Mints
Mr. Krabs created a secret ingredient for a breath mint that he thinks will "cure the bad breath people get from
cating crabby patties at the Krusty Krab. He asked 100 customers with a history of bad breath to try his new
breath mint. He had fifty customers (Group A) cat a breath mint after they finished eating a crabby patty. The
other fifty (Group B) also received a breath mint after they finished the sandwich, however, it was just a regular
breath mint and did not have the secret ingredient. Both groups were told that they were getting the breath mint
that would cure their bad breath. Two hours after cating the crabby patties, thirty customers in Group A and ten
customers in Group B reported having better breath than they normally had after cating crabby patties.
1. Which people are in the control group?
2. What is the independent variable?
3. What is the dependent variable?
4. What should Mr. Krabs' conclusion be?
5. Was this a quantitative or a qualitative measurement?
6. Why do you think 10 people in group B reported fresher breath?

Answers

Answer:

1. Which people are in the control group? The people who received the mint without the secret ingredient

(Group B) would be the control group.

2. What is the independent variable? Secret ingredient in the breath mint

3. What is the dependent variable? Amount of breath odor (or bad breath)

4. What should Mr. Krabs’ conclusion be? The breath mint with the secret ingredient appears to reduce the

amount of breath odor more than half the time, but it is not 100% effective.

5. Why do you think 10 people in group B reported fresher breath? This may be due to the placebo effect.

Sulfur and oxygen form both sulfur dioxide and sulfur trioxide. When samples of these are decomposed, the sulfur dioxide produces 3.52 g oxygen and 3.53 g sulfur, while the sulfur trioxide produces 9.00 g oxygen and 6.00 g sulfur.
Calculate the mass of oxygen per gram of sulfur for each sample and show that these results are consistent with the law of multiple proportions

Answers

Answer:

See explanation

Explanation:

For sulphur dioxide;

3.53 g of sulphur combines with 3.52 g of oxygen

1.00 g of sulphur combines with 1.00 × 3.52/ 3.53 = 0.997 g

For sulphur trioxide

6.00 of sulphur combines with 9.00 g of oxygen

1.00 g of sulphur combines with 1.00 × 9.00/6.00 =1.5 g

Ratio of mass of oxygen;

1 : 1.5

The law of multiple proportions states that, if two elements A and B combine to form more than one chemical compounds, then the various masses of element A which combines separately with a fixed mass of element B are in simple multiple ratio.

We can see that the mass of oxygen which combines separately with sulphur in sulphur dioxide and sulphur trioxide are in simple ratio of 1:1.5.

Will a deflated football sink in water?

Answers

Answer:

no

Explanation:

light objects float

No it will float it’s lighter

Chromium(III) oxide reacts with hydrogen sulfide (H_2S) gas to form chromium(III) sulfide and water:______.
Cr_2 O_3 (s) + H_2S (g) ? Cr_2S_3 (s) + 3H_2O (l)
To produce 346 g of Cr_2S_3,
(a) how many moles of Cr_2 O_3 are required?
......... mol
(b) how many grams of Cr_2 O_3 are required?
......... g

Answers

Answer:

a. 1.728 moles.

b. 262.7g of Cr₂O₃ are required

Explanation:

Based on the reaction:

Cr₂O₃(s) + 3H₂S(g) → Cr₂S₃(s) + 3H₂O(l)

The important thing in the reaction is that 1 mole of Cr₂O₃ produce 1 mole of Cr₂S₃

a. To produce 346g of Cr₂S₃ we must know how many moles of Cr₂S₃ must be produced, and, as 1 mole of Cr₂O₃ produce 1 mole of Cr₂S₃ we can know moles of Cr₂O₃ that are required.

Moles of 346g Cr₂S₃ (Molar mass: 200.19g/mol):

346g Cr₂S₃ * (1mol / 200.19g) = 1.728 moles of Cr₂S₃

Based on the reaction, moles of Cr₂O₃ that are required are

1.728 moles of Cr₂O₃

b. Again, to conver the 1.728 moles of Cr₂O₃ to grams we must use molar mass of Cr₂O₃ (151.99g/mol):

1.728 moles Cr₂O₃ * (151.99g / mol) =

262.7g of Cr₂O₃ are required
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A hot air balloon starts at a height of 6 feet above the ground and then rises at a rate of 20 feet each minute. Which equation gives the height h in feet as a function of time t in minutes? Oh=6t Oh = 20$ Oh=20t + 6 Oh=6+ 20 Why is it important to site? Name at least three reasons In the reaction of silver nitrate with sodium chloride, how many grams of silver chloride will be produced from 100. g of silver nitrate when it is mixed with an excess of sodium chloride? The equation for the reaction is below. AgNO3 + NaCl AgCl + NaNO3 A new electronic store opened recently. There are several sales associate positions that pay an hourly rate of $7.50 plus a 4.5% commission based on the sales associates total weeking sales. Sales assqqociates are guaranteed 30 hrs of work per week,but no more that 40 hrs. At the electronics store, sales associates average $7,000 in sales each week. USE THE AVERAGE WEEKLY SALES FIGURE OF $7,000 AND HOURLY RATE OF $7.50. WRITE AN EQUATION, CREATE A TABLE, AND CREATE A GRAPH FOR A SALES ASSOCIATE'S WEEKLY EARNINGS, f(x), where x represents the total number of hours the sales associate would work. Cmo las medidas adoptadas en situaciones de pandemia repercuten al bienestar emocional? The mixture is green in color. This confirms that the mixture is a.... A) suspension B) solution C) colloid D) this proves nothing What is another way to name plane T? Question 9 of 10A team of engineers has decided to design a new shoe for people sufferingfrom a painful foot condition. What should the engineers do during theplanning stage of their project?A. Look at the trial's results to see how the design can be improved.O B. Estimate how much potential consumers would be willing to payfor this new shoe.C. Have patients wear the new shoe in an experimental trial to see ifsymptoms improve.D. Build a variety of shoe models. IWhich of the following is NOT an effect of anxiety?.It can make you avoid normal routines.BIt can help you to avoid violence,It can lead to you avoiding friends.DIt can make you avoid public speaking, identify balance chemical equation from the following C+O2=CO2H2+O2=H2O2PbO+C=Pb+CO2Fe2O3+2Al=Al2CO3+2Fe If a substance weighs 2.00 grams and you need the mass in kilograms, will the number appear to become smaller or larger? Creating a favorable impression and building trust with prospective customers is a critical part of the __________ step of personal selling. AC = 23. AB = 2x + 2, and BC = 3x + 6. Find BC How was the ancient Roman family organized A.The children were on the same level as the family servants B.All members of the family had equal rights but separate roles C.The mother and father shared property and had equal power D.The father had complete control over all members of the family What are the critical points for the plane curve defined by the equations x(t)=t 33t222t4y(t)=t322t+2 what is the definition of a radical How are domains and kingdoms similar Which separation technique will be used by a lady for the separation of dirt from clothes in washing machine? How did Gerda Seifer survive the holocaust? If Congress cuts spending to balance the federal budget, the Fed can act to prevent unemployment and recession by