Correct Answer: D

Rationale: The correct answer is "epigastric." The epigastric region is located in the upper midportion of the abdomen, between the hypochondriac regions on either side. Choice A, "hypochondriac," refers to the upper lateral regions of the abdomen beneath the ribs. Choice B, "iliac," pertains to the lower lateral regions of the abdomen. Choice C, "hypogastric," is the lower central region of the abdomen.

Correct Answer: A

Rationale: The correct answer is 'tissues, which build organs.' Specialized cell types organize to form tissues, which in turn build organs. Tissues are groups of cells that work together to perform a specific function. Option B is incorrect because organs are composed of tissues, not the other way around. Option C is incorrect as organ systems consist of multiple organs working together, not building tissues. Option D is incorrect as atoms are the basic building blocks of matter and are not directly involved in forming tissues.

Correct Answer: C

Rationale: The correct answer is C: 'bilateral.' Paired organs like the kidneys or lungs are described as bilateral because they occur in pairs on both sides of the body. Option A 'bisexual' refers to having both male and female reproductive organs, which is not the correct term for paired organs. Option B 'bilingual' refers to being able to speak two languages, which is not related to the description of paired organs. Option D 'bivalent' means having two valences, which is also unrelated to the context of paired organs.

Correct Answer: C

Rationale: Blood cells are produced in the organs of the hematopoietic system. The correct answer is 'superior to' as this refers to the location of the organs responsible for blood cell production, typically bone marrow found in bones such as the vertebrae, ribs, and skull. 'Endocrine' (Choice A) refers to a different system responsible for hormone production. 'Skeletal' (Choice B) relates to bones but not specifically to the production of blood cells. Choices C and D, 'superior to' and 'inferior to,' do not make sense in the context of blood cell production and are incorrect.

Correct Answer: D

Rationale: The correct answer is 'negative feedback mechanisms.' In biological systems, negative feedback mechanisms help maintain homeostasis by counteracting any deviations from the set point. They work to stabilize internal conditions and keep them within a narrow range. On the other hand, positive feedback mechanisms amplify changes and are not involved in maintaining stability. Choice B, 'an unstable outside environment,' is incorrect as internal stability is independent of external conditions like weather. Choice C, 'decreased atmospheric pressure,' is also incorrect as it does not directly relate to internal homeostasis.