How many valence electrons does carbon have and why is it important?

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Will mark you as ! keiko’s teacher was discussing the theory of endosymbiosis. she asked keiko to mark the organelles in the diagram that most closely resembled prokaryotes. which organelles should keiko mark? * the first image is the question and the second image is some information to you answer the !

8) animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. d) a dog is getting hot in the sunlight, so he moves to a shaded area.