Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Ex Input:
Question: Predators can replace what tool in agriculture. Answer: pesticides

Ex Output:
Predator species such as birds and spiders control insect pests. They reduce the need for chemical pesticides, which are expensive and may be harmful to human beings and other organisms.

Ex Input:
Question: What type of mammals are humans? Answer: placental mammals

Ex Output:
Human beings are mammals. Like other mammals, we have hair and mammary glands. The subclass in which the human species is classified is the placental mammals.

Ex Input:
Question: What is the general shape of centrioles? Answer: rod

Ex Output:
Centrioles are rod-like structures made of short microtubules. Though they are found in most eukaryotic cells, centrioles are absent in some plants and most fungi.