Well there's a couple reasons why. First, the land itself can become “tired" and less fertile<span>. This is because the same type of </span>crop<span> planted repeatedly in the same area keeps draining the land of the same nutrients needed for that plant's growth. Pest can also plant their nest near the crop if the farmer continues to plant the same crop in the same place.
Which is the reason why things such as "crop rotation" exist to keep things fresh, and prevent what I described above from happening.</span>
Answer:
333.7g of antifreeze
Explanation:
Freezing point depression in a solvent (In this case, water) occurs by the addition of a solute. The law is:
ΔT = Kf × m × i
Where:
ΔT is change in temperature (0°C - -20°C = 20°C)
Kf is freezing point depression constant (1.86°C / m)
m is molality of solution (moles solute / 0.5 kg solvent -500g water-)
i is Van't Hoff factor (1, assuming antifreeze is ethylene glycol -C₂H₄(OH)₂)
Replacing:
20°C = 1.86°C / m × moles solute / 0.5 kg solvent × 1
5.376 = moles solute
As molar mass of ethylene glycol is 62.07g/mol:
5.376 moles × (62.07g / 1mol) = <em>333.7g of antifreeze</em>.
Answer:
A. move materials through the body
Explanation:
The blood circulatory system (cardiovascular system) transports materials and delivers nutrients and oxygen to all cells in the body.
