Amale body contains 5 to 6 liters of blood, whereas a female body contains 4 to 5 liters. why do you think there is a difference between the two?

There are a couple of reasons why men have a higher blood volume than women, and here are some of them:
1. they are taller - given that usually male bodies are larger than those of women, they need more blood to flow through such a vast vessel
2. men have testosterone - this hormone increases the production of erythrocytes, or red blood cells
3. women menstruate - during this period of month, women lose a portion of the blood, which is why they have less 

C) It helps us understand the differences and similarities among living things

Explanation:

We split species into kingdoms based on their traits, so animals with similar traits will go to one kingdom and one with different traits will go to another. It helps us see similarities and differences in different species.