<span>There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart</span>
Answer:
Animals preserve play very important role in maintaining ecosystem biodiversity. In animal preserves, animals are protected from the harmful effects of the changes which occur in the environments due to human intervention. In animal preserves,
animals should be kept in proper environment and provide a proper place for living and food in order to increase the population of the animals.
I think you're confused. There are only two sexes, male and female. Sex is what you were biologically born as from birth, while gender is what you choose to identify as. Gender is a choice, sex isn't. They couldn't discover any other genders because at the time they probably didn't even know what gender was like three thousand years ago, therefore they couldn't look like a different gender.