Answer:
Red blood cells are formed in the red bone marrow of bones
Hello TeamFlow, They are all living things, they all need some sort of nutrition, and all plants like fungi, moss, grass etc, have cells. :)
Threatened means they are lowering in numbers and nearing to be endangered.
Endangered means they are dangerously close to being extinct
Extinct means there is none of them left in the wild.
I hope this is what you meant.
There are four major classes of biological macromolecules:
carbohydrates.
lipids.
proteins.
nucleic acids.