It means that only those who are able to adapt with all conditions they are placed in will be able to live.
A+,A-,O+ and O- can give to blood type A+
Capillaries: <span>any of the fine branching blood vessels that form a network between the arterioles and venules.</span>
ADH is also called arginine vasopressin. It's a hormone made by the hypothalamus in the brain and stored in the posterior pituitary gland. It tells your kidneys how much water to conserve. ADH constantly regulates and balances the amount of water in your blood.
(My source was www.healthline.com in case you wanted to investigate for yourself. Hope this helps!)
Trace fossils represent things that were alive, it could be footprints, or bones.
I think this option fits best:
"<span>Evidence that animals were at some time in the area."</span>
