It’s b.
He grouped the types of creatures according to their similarities: animals with blood and animals without blood, animals that live on water and animals that live on land.
I think it’s Cytokinesis.
Answer:
Senior mothers are also under pressure to share food with their sons, so that they're able to reproduce as well. It also makes sense for these mothers to assist their sons because as the mothers grow older, they are increasingly related to whales in other, neighboring pods via their sons' calves.
I think salt is it
........................
Transverse waves contain crests & troughs
while longitudinal waves contains compressions &rarefactions.