A sodium atom that has lost an electron comes near a chlorine atom that has gained an electron. What happens? A. They form a peptide compound.
B. They form a covalent bond.
C. They form a hydrogen bond.
D. They form an ionic bond.

Plzzz hurry im being timed ! humans, like other organisms, require energy for growth and repair. when cells create atp for energy, carbon dioxide is produced as a waste product. how does the body respond to this process in order to maintain homeostasis? a. the digestive and respiratory systems interact to move carbon dioxide to the lower intestine, where it is transformed into methane. b. the circulatory and digestive systems interact to move carbon dioxide to the stomach, where it to break down food. c. the nervous and urinary systems interact to move carbon dioxide to the kidneys, where it is absorbed into the bloodstream. d. the circulatory and respiratory systems interact to transport carbon dioxide to the lungs, where it is expelled from the body.

Creation of an unnaturally uniform sample to represent a diverse populationcan be avoided by: a. including only willing b. asking another scientist for .c. choosing only identical participants.d. selecting individuals at random.

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.