In summer they're cooler and during winter they're warmer
They both act like filters. The coffee filter makes sure that coffee doesn't go in the drink and the kidney makes sure solids don't pass by.
Here's a graph showing the stages.
Look closely at the second stage-- the death rate is low but the birth rate is high.
It's <span>
D. The death rate begins to fall, but birth rates remain high for a time.</span>