What is the advantage of the folds of nervous tissue in the brain?
The brain has folds for the same reason our intestines do: It increases surface area and makes more “active” tissue in a smaller place. For your second question, the answer is b, but should really be d, as the question assumes that the Platypus is the only egg-laying mammal. There are actually 3: The platypus, and two species of echidna. And unless there is a typo and the “for” was meant to be “from”, the answer is “C”. Hair, as in the case of humans, is used as insulation, and in the case of zebras, tigers, and other animals, the color of hair can be used as camouflage.
