3: B Nervous system. 4: A Sensing and responding to its external environment.
Answer: D)
Membrane proteins produce phospholids
Explanation:
Membrane proteins in the mitochondria do more than just generate cellular energy. The proteins in the membranes of the mitochondria are complex machines in the nanoworld that mediate the oxygen-coupled generation of energy in cells. Their role in this process is not yet understood in detail.
Membrane proteins perform a variety of functions vital to the survival of organisms: Membrane receptor proteins relay signals between the cell's internal and external environments. Transport proteins move molecules and ions across the membrane.
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>