43. Which of following is NOT true?
(A)Amino acid neurotransmitters are active in the vertebrate CNS and PNS.
(B)Binding of GABA to receptors in postsynaptic cells increases membrane permeability to potassium.
(C)The biogenic amine serotonin made from tryptophan.
(D)In the PNS, CO acts as an inhibitory neurotransmitter that hyperpolarized the plasma membrane of intestinal smooth muscle cells.
(E)In the CNS, the amino acid glutamate is the most common neurotransmitter.

39. The descending portion of the loop of Henle is (A)permeable to water and impermeable to sodium. (B)permeable to water and permeable to sodium. (C)impermeable to water and permeable to sodium. (D)impermeable to water and impermeable to sodium. (E)the site of active transport of water

40. ________ is a water-soluble hormone derived from the nervous system that regulates blood volume and blood pressure? (A)Antidiuretic hormone (B)Aldosterone (C)Cortisol (D)Oxytocin (E)Adrenocorticotropic hormone

41. The ectoderm is to the central nervous system as the mesoderm is to the (A)epidermis. (B)respiratory tube. (C)digestive tract. (D)skeletal muscle. (E)peripheral nervous system. 

42. The clonal selection theory is an explanation for (A)how a single type of stem cell can produce both red blood cells and white blood cells. (B)how antibody proteins can be molded to fit antigens after the antigen interacts with the antibody-producing type of cell. (C)how an antigen can induce the multiplication of very few cells to result in production of high levels of specific antibodies. (D)how HIV can disrupt the immune system. (E)how macrophages can recognize specific T cells and B cells.

44. Patterns of species change and succession are one focus of (A)behavioral ecology. (B)environmental science. (C)biological control. (D)community ecology. (E)physiological ecology.

45. What is the process through which many animals develop irreversible species-specific behavior patterns? (A)altruism (B)taxis (C)operant conditioning (D)cognitive learning (E)imprinting

46. Organisms that produce all of their offspring in a single event are (A)always successful. (B)never successful. (C)autogenous. (D)semelparous. (E)iteroparous.

47. Similar species can coexist in a community because of (A)resource partitioning. (B)competitive exclusion. (C)allopatric competition. (D)sympatric competition. (E)allopatric competition and sympatric competition. 

48. Ecosystem ecology is primarily concerned with (A)ecosystem stability. (B)interactions among species. (C)the synthesis of new forms of nutrients. (D)patterns of species diversity. (E)movement of energy and materials through organisms and their communities.

49. Species that create, modify and maintain habitat are known as (A)indicator species. (B)keystone species. (C)dominant species. (D)SLOSS builders. (E)ecosystem engineers.