Prolactin is responsible for causing milk production in women.

Luteinizing hormone stimulates ovulation; the LH surge is caused by a positive feedback mechanism in which estrogen elicits the release of luteinizing hormone. The thyroid hormones generally regulate metabolism, and are themselves regulated by thyroid-stimulating hormone. Antidiuretic hormone and aldosterone indirectly regulate the acid-base balance of the body by adjusting reabsorption rates in the excretory system. The presence of these hormomes leads to water retention, which will dilute the blood. Oxytocin stimulates contractions during labor.

Antiduretic hormone (ADH) is alternatively known as vasopressin. It is secreted from the posterior pituitary gland and acts on the collecting ducts of the kidney to facilitate the reabsorption of water. Thus, ADH reduces the volume of urine formed, and increases blood volume.

In the passage it is stated that hCG is detected in the urine. In order to get there, the hormone must be filtered from the blood into the kidney tubules (via the glomerulus). The tubules must then not reabsorb all of it back into the blood; instead, the hCG must be allowed to leave in the urine. The other answer choices can be eliminated after consideration. The answer choice, 'hCG is also secreted by the mother', is wrong because hCG is only secreted by the fertilized embryo; if it was also secreted by the mother, the pregnancy test would not be effective because hCG could be detected in non-pregnant mothers.

In either case, the passage does not imply that the mother makes hCG. Answer choice, 'hCG does not enter the mother's bloodstream', can be eliminated because the passage directly states that hCG is released into the mother's bloodstream. The answer choice, 'The actions of progesterone are counteracted by hCG', is wrong because hCG works to maintain the corpus luteum, which secretes progesterone. If anything, hCG works to maintain the production and function of progesterone, not counteract it. 

Answering this question simply requires picking the answer choice that doesn't have anything in common with the others. Conditions in which specific antibodies are produced which might be tested for using the same technique are described in the passage. After all, antibodies are proteins, and monoclonal antibodies can be made to detect them. HIV infection can be detected by assaying for the antibodies against HIV.Arthritis can be detected by looking for antibodies against "self" proteins. Strep throat can be detected by directly assaying for the presence of bacterial proteins. The same technique which was used to detect hCG can be used in these instances. Tryptophan blood levels, however, cannot be determined using the same methodology. For one thing, tryptophan (an amino acid) does not elicit antibody production. Secondly, the actual levels of substances in the blood can't be detected by the type of test described in the passage. This test yields either a "present" or "not-present" result

Simple squamous epithelium is a single layer of flat cells that is found in areas where passive transfer takes place. This includes the blood vessels (capillaries), the alveoli, and the glomerulus. The capillaries and alveoli are specialized for diffusion and osmosis, while the glomerulus is specialized for filtration.

Absorption is typically associated with simple columnar epithelium (found in the small intestine) and simple cuboidal epithelium (found in the nephrons).

Stratified squamous epithelium is primarily associated with protection of the body, and is found in areas that commonly encounter stress. These areas include the skin, the tongue, and the esophagus. The small intestine is associated with absorption, and is lined with simple columnar epithelium.

Thermoregulation is a homeostatic mechanism for regulating body temperature in varying conditions. This is accomplished by physiological, structural, and behavioral mechanisms. For example, many mammals will shiver as a result of small muscle contractions to generate heat. Many of the other possible answers sound similar, but are incorrect. Thermoregulation is a type of environmental adaptation, but "adaptation" is too broad of an answer in this case.

All of these mechanisms are used to either increase or decrease body temperature, allowing for proper temperature regulation. When your body becomes cold, shivering (the result of involuntary muscle contractions) helps increase body temperature. Constriction of blood vessels diverts warm blood to the most critical organs and away from extremities. In hot temperatures, blood vessels dilate to allow more blood to the surface of the skin where heat exchange can occur. Sweating allows excess heat to be released through the evaporation of water. Without all of these mechanisms, humans would have difficulty surviving in all the environments we currently inhabit around the world.

This question is asking for a thermoregulatory mechanism that is NOT active in response to an increase in temperature. Preference for a cooler environment would be an apt response to increased temperature. Activation of sweat gland excretion would secrete liquid onto the skin's surface—the evaporation of this liquid carries heat away from the skin. Dilation of arteriole sphincters would increase overall blood flow, which carries heat, to the skin; this heat can dissipate to the environment. Decrease in skeletal muscle activity would lead to less metabolic activity and subsequent heat production.

The pilorection of hairs on the skin surface would not be an appropriate response to a temperature increase. This is because when erect, hairs would reduce the flow of air over the skin and retain body heat. Goosebumps are formed in pilorection, and this is typically seen in a response to cold temperatures.

Beneath the surface of the skin, erector muscles are attached to hairs. When it is cold these muscles contract, causing hair to stand up. When hair stands it creates a collective mass of air that maintains temperature by lowering drafts. The erect hairs essentially dull the effects of convection heat transfer by trapping warm air against the skin.