6. Among vertebrates, single circulation is found in_________.
(A) Actinopterygii
(B) Amphibia
(C) Aves
(D) Mammalia

(E) Reptilia

2. Increased permeability to__________results in hyperpolarization in a neuron.(A) Ca+(B) H+(C) K+(D) Mg2+(E) Na+

3. Which of the following events is NOT triggered by a calcium second messenger?(A) Propagation of action potential along an axon(B) Cortical reaction resulting in the formation of the vitelline envelope(C) Cortical rotation resulting in the formation of grey crescent in frog egg(D) Muscle contraction(E) Release of neurotransmitters from synaptic vesicles

4. Bohr shift is an effect of pH on_________.(A) the rate of breathing(B) the quantum efficiency of opsin(C) the solubility of protein(D) the affinity of hemoglobin for O2(E) the reabsorption of H2O

5. Among hormones regulating human reproduction, the receptor of_________is NOT a transmembrane protein.(A) follicle-stimulating hormone(B) estradiol(C) gonadotropin-releasing hormone(D) inhibin(E) luteinizing hormone

7. In animals, a chemical used to communicate with conspecific individuals is called _________.(A) autocrine(B) a ligand(C) a hormone(D) a neurotransmitter(E) a pheromone

8._________is found in Metazoa only and not in other eukaryotes.(A) Alternation of generations(B) Collagen fiber(C) Dikaryon(D) Heterotrophy(E) Multicellularity

9._________is NOT a feature of adaptive immunity.(A) Antibody(B) Clonal selection(C) Humoral immune response(D) Natural killer cell(E) Major histocompatibility complex molecule

10. During vertebrate embryonic development, the retina is derived from _________.(A) forebrain(B) midbrain(C) hindbrain(D) lens placode(E) prechordal mesoderm

11. Which of the following statements about the antidiuretic hormone (ADH) is true?(A) It is a peptide hormone released from the adrenal gland.(B) In the absence of ADH, the ability to reabsorb water in the proximal tubule would be lost.(C) It promotes the excretion of hyperosmotic urine (compared to plasma).(D) Decreased plasma osmolarity stimulates ADH secretion.(E) Blood pressure would increase significantly if a person lost the ability to synthesize ADH.

12. Chronically high levels of glucocorticoids can result in obesity, muscle weakness, and depression, a combination of symptoms called Cushing's syndrome. To determine which gland has abnormal activity in a particular patient, doctors use the drug dexamethasone, a synthetic glucocorticoid that blocks ACTH release. Based on the graph, identify which gland is affected in patient X, whose ACTH level in blood is effectively lowered by dexamethasone.(A) Adrenal medulla(B) Adrenal cortex(C) Anterior pituitary(D) Posterior pituitary(E) Thyroid gland