Please I have so much more to do.

The correct answer is D. Skeletal system.

Explanation

The parathyroid glands are glands of the human endocrine system that are located behind the thyroid glands in the neck. The main function of the parathyroid glands is to control the amount of calcium in the body (mainly bones and blood). According to the above, the parathyroid glands produce essential hormones for the proper function of the bone system because it controls the calcium that is used to strengthen the bones. These at the same time serve as the storage system to ensure that the body always has a vast source of calcium. So the correct answer is the D. Skeletal system.

answer: zinc is the substance which has a volume of 1.38 .

density is defined as the mass of an object per unit volume.

it can be calculated by dividing mass of a substance by its volume i.e.

si unit of density is kg per cubic meter and cgs unit of the same is gram per cubic centimeter.

now from the given data volume can be calculated by the formula .

hence, the volume of aluminium will be = which comes out to be 1.703 .

similarly, volume of zinc, chromium, and nickel will be 1.378 , 0.869 , and 0.356 respectively.