the nitrogen cycle involves decompisition. and the waste from the animals is then turned into nitrogen.
Humans get there energy primarily from glucose I believe. We break down glucose to get ATP (Adenosine Triphosphate) which is then used to supply energy to our cells in order to function.
Yes, they ate the only mammals which could fly because flying squirrels, possums or etc. could only glide for a short distance and time, unlike bats. There are no reptiles who could fly, but there are reptiles who could glide which I think is completely different. But they said that Pterosaur existed which they believed it is a flying reptile dinosaur. Just look it up. :)
On day one the levels of oestrogen and progesterone are low, having dropped quickly at the end of the last cycle. Low oestrogen level causes FSH release from the pituitary gland.
1. is the second answer I believe and 2. is the first answer
I hope this helps