Write an essay on the respiratory system of a human being.

The respiratory pigment in human beings is

The ultimate end parts of the respiratory system in human are known as:

The ultimate end parts of the respiratory system in humans are known as

Describe, in brief, the circulatory system in human beings.

Write an essay on abiotic factors.

The most important muscular structure in respiratory system of human is

Which of the following is not a part of the respiratory system of Periplaneta americana ?

Which pollutant mainly affect the respiratory system in human and animals ?

Write an essay on the composition of blood.

What are the components of the transport system in human beings? What are the functions of these components?