A heat engine gives greater efficiency when run with a large temperature difference. In the oceans the temperature difference between surface and deep water is greatest in the tropics, although still a modest 20 to 25 Â°C.
A blastocyst is a cellular mass that forms early in the process of embryo development in mammals. In humans, this stage of embryogenesis occurs five days after fertilization, when there are fewer than 100 cells in the mass.
Each cnidae is located within a specialized cell that houses it, this cell is a capsule with an attached hollow thread. Nematocyst is the more familiar term applied to specialized cnidae that are characteristic of scyphozoan and other types of jellies, and other cnidarians. As to the functions: stinging nematocysts function primarily for the capture of prey, and secondarily as a defense mechanism. There are many types of nematocysts, such as those that function to inject toxins to immobilize prey, and those which serve to entangle and hold onto the intended meal by wrapping around it.