PLEASE HELP ME FAST! Of the many functions of the skeletal system, which is directly helpful to the circulatory system?

A. stores calcium and phosphorus
B. provides an attacment point for muscles
C. produces blood cells
D. provides shape and support for the body
E. protects internal organs

c

Explanation:

answer; i believe the correct answer is (anemia);

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.