Answer:
A. proteins
Explanation:
Amino acids builds up the proteins.
Answer:
(a) Allow movement in only one plane/direction (that is extension or flexion)
(b) The skeletal system also produces blood cells in their bone marrow
Mesoderm
Mesoderm is the primary germ layer that is responsible for producing both blood and phagocytic brain glial cells.
The mesoderm is the middle of the three germ layers that appears in the third week of embryonic development. The mesoderm is responsible for the formation of various body structures such as epithelia of blood vessels, blood, muscle, bone, phagocytic brain glial cells, lymphatic vessels, adrenal cortex, notochord, and bone marrow.
