Answer:
B
Explanation:
You have three stages for analyzing.
You start at B with a tiny free-swimming larva.
Some of those larvas start making segmentation. It is an evolutionary trait.
This divide what we today know as gastropods and those animals that continue with evolution.
Those segmentation larvas also evolve with a molten external skeleton which made them all crustaceans as we know them today.
Crab and barnacle are differentiation into the crustaceans.
If one amoeba dies then two amoeba get born:
at different stages of the generations of the amoeba it changes accordingly and the died amoeba numbers are also change in the given manner :
stages dies born
I 1 2
II 4 =
III 8 =
At =
By the geometric series formula:
1++ + ...+ =
so, 1++ + ...+ =
Thus, total amoeba died = -1
total amoeba died+1 = (born).... hence prooved
D. Tree roots improve soil water retention