Many insects have a tough outer shell called an exoskeleton cellulose an endoskeleton chitin

An exoskeleton.

Explanation:

Tough outer shell of many insects is known as exoskeleton that represents an external skeleton. The exoskeleton provides protection and support to the insects body as they lack an internal skeletal system as higher organisms. In insects, it is made up of chitin.

Exoskeleton also plays role in sensing, feeding, excretion, and protection against desiccation in land insects.

Thus, the correct word to be filled in the blank is 'exoskeleton.'

what is the statement?

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.