What is the name of the muscular ring that controls the passage of food from the esophagus to the stomach?

Correct Answer: B

Rationale: The correct answer is the Cardiac sphincter (lower esophageal sphincter). It is situated at the junction of the esophagus and the stomach, controlling the passage of food into the stomach. The cardiac sphincter opens and closes to regulate the flow of food and prevent reflux. The pyloric sphincter, on the other hand, is located between the stomach and the small intestine, not the esophagus and stomach. The ileocecal valve is positioned between the small and large intestines, while the Sphincter of Oddi is found in the duodenum, not between the esophagus and stomach.

Correct Answer: B

Rationale: The primary function of the lymphatic system is to remove excess fluids, waste products, and toxins from tissues. It maintains fluid balance and supports the immune system by transporting lymph, which contains white blood cells, throughout the body. Choice A is incorrect as nutrient transport is primarily handled by the circulatory system. Choice C is incorrect because red blood cells are produced in the bone marrow, not the lymphatic system. Choice D is incorrect as the regulation of body temperature is mainly controlled by the endocrine system and thermoregulatory mechanisms in the body. Therefore, the correct answer is B.

Correct Answer: A

Rationale: The correct answer is A. The innate immune system provides nonspecific, immediate defense against pathogens. It is the body's first line of defense in responding to infections and does not involve memory cells or specific long-term immune responses like the adaptive immune system. Choice B is incorrect because specific, long-term immune responses through memory cells are characteristics of the adaptive immune system, not the innate immune system. Choice C is incorrect because the innate immune system does not provide specific, long-term immune responses. Choice D is incorrect because the innate immune system does provide an immediate defense against pathogens.

Correct Answer: D

Rationale: Theta waves are the correct answer as they are often seen during REM (rapid eye movement) sleep, the stage of sleep closely related to dreaming. Theta waves have a frequency of 4-7 Hz and are typically present during deep relaxation, meditation, and light sleep stages. Delta waves (choice A) are associated with deep sleep stages, not REM sleep. Alpha waves (choice B) are present during wakefulness and relaxation but not predominantly during REM sleep. Beta waves (choice C) are associated with alertness, problem-solving, and active thinking, not specifically with REM sleep or dreaming.

Correct Answer: D

Rationale: Adipose tissue, also known as fat, serves multiple essential functions in the body. It provides support by cushioning and protecting organs, acts as an insulator to help regulate body temperature, and serves as a major energy storage site by storing excess energy in the form of triglycerides. Therefore, all the options (support, insulation, and energy storage) are correct functions of adipose tissue, making 'All of the above' the correct answer. Choices A, B, and C are all individually valid functions of adipose tissue, but to encompass the comprehensive role of adipose tissue, 'All of the above' is the most accurate option.