Examine the digestive system structures in the figure above. The agent(s) that help emulsify fats are produced in location.

9 — bile is formed in the liver

The most enzymatic hydrolysis of macromolecules occurs at location(s)

4 only. — small intestine

Most of the digestion of fats occurs in location(s)

4 only. — small intestine

If you were to jog 1 km a few hours after lunch, which stored fuel would you probably tap?

muscle and liver glycogen

Blood returning to the mammalian heart in a pulmonary vein drains first into the

left atrium

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?

rising CO₂

If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except

the pulmonary vein

Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells?

B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.

Which of the following statements is not true?

A lymphocyte has receptors for multiple different antigens.

Peaks of LH and FSH production occur during

the period just before ovulation.

Homeostasis typically relies on negative feedback because positive feedback

drives processes to completion rather than to a balance point

Which of the following organs is incorrectly paired with its function?

large intestine - bile production

Which of the following is true of innate behaviors?

Innate behaviors are expressed in most individuals in a population across a wide range of environmental conditions.

Which of the following is not required for a behavioral trait to evolve by natural selection?

In each individual, the form of the behavior is determined entirely by genes.

During the contraction of a vertebrate skeletal muscle fiber, calcium ions

bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

Myosin filaments without actin overlap are in which section of the figure?

D - 4

Z-line

C - 3

Where are neurotransmitter receptors located?

the postsynaptic membrane

Why are action potentials usually conducted in one direction?

The brief refractory period prevents reopening of voltage-gated Na+ channels.