Internal temperature, I believe.
They are attacked by lymphocytes.
B. earlier invention, C. education through social media, & D. ending food inspection programs
Cooperation (sometimes written as co-operation) is the process of groups of organisms working or acting together for common, mutual, or some underlying benefit, as opposed to working in competition for selfish benefit
Many animal and plant species cooperate both with other members of their own species and with members of other species (symbiosis or mutualism)
Humans cooperate for the same reasons as other animals: immediate benefit, genetic relatedness, and reciprocity, but also for particularly human reasons, such as honesty signaling (indirect reciprocity), cultural group selection, and for reasons having to do with cultural evolution
This system helps the respiratory system by protecting the lungs. The circulatory system is very useful. This system transports the food nutrients, and oxygen to the body cells. It also delivers of carbon dioxide and waste products.