When i say apes i mean monkeys
First question: tailbones, how other animals evolved
Second question: apes had tailbones, other animals have evolved.
Third Question: Both humans and apes had tailbones, shows that evolution does exist.
It's an important part of the bird's ability to maintain its body temperature.
Air is a poor conductor of heat, so the air trapped among the feathers
prevents the loss of heat in cold atmosphere, and prevents overheating
in hot atmosphere. Much like our wearing several layers of clothing.
Answer: The deep-sea organisms found today have undergone evolution in the past and are very complex now because their body structure also varies from that of the organisms that are present at a lower depth.
The bodies of these organism does not contain any air cavities in which the pressure could exert. It is because of this, the organism are quite solid without any air in their bodies, thereby they can withstand extreme high pressure.
Pairs of Chromosomes are called Sex cell pairs. Sex cells, like sperm and egg, have only a set of Chromosomes called "Daughter Cells". Sorry I didn't do all of your questions, I could only find some of the answers.