The forearm consists of the:
radius and ulna
radius and humerus
ulna and humerus
humerus and carpus

Radius and Ulna.

Those are the long bones that together form the forearm.

The external bone is the radius, and the inside bone is the ulna, they are joint by its extremes.

The humerus is the bone that forms the arm.

Carpus is a conjunction of bones that form the wrist.

links? do you have a link? i don't see anything?

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.