Which is a nutritionally essential amino acid?

Correct Answer: B

Rationale: Rationale for correct answer (B - leucine): Leucine is an essential amino acid, meaning it cannot be synthesized by the body and must be obtained through diet. It plays a crucial role in protein synthesis, muscle repair, and growth. It is essential for overall health and well-being. Summary of why other choices are incorrect: A - taurine: Taurine is a conditionally essential amino acid, not nutritionally essential. C - glutamate: Glutamate is a non-essential amino acid, as the body can synthesize it. D - alanine: Alanine is a non-essential amino acid, as the body can also produce it.

Correct Answer: B

Rationale: The correct answer is B, antidiuretic hormone (ADH). ADH regulates the body's fluid balance by controlling the amount of water reabsorbed by the kidneys. This helps maintain proper hydration levels and electrolyte balance. Adrenocorticotropic hormone (A) regulates cortisol production, not fluid balance. Luteinizing hormone (C) plays a role in reproductive functions, not fluid balance. Option D is incorrect because only antidiuretic hormone is directly involved in regulating fluid and electrolyte balance.

Correct Answer: C

Rationale: The correct answer is C: Acid. The stomach produces hydrochloric acid to aid in digestion by creating an acidic environment that helps break down food and kill bacteria. Alkali (A) would not aid digestion as it neutralizes acids. Trypsin (B) and Amylase (D) are enzymes produced in the pancreas, not the stomach, and play a role in digesting proteins and carbohydrates, respectively. Thus, they are not the products of the stomach for aiding digestion.

Correct Answer: A

Rationale: The correct answer is A because hormones and neurotransmitters are both chemical messengers that can sometimes be chemically identical and produce molecules that act on receptors in target cells. This is correct as both hormones and neurotransmitters are signaling molecules that carry messages between cells. Choice B is incorrect because hormones typically travel through the bloodstream to reach target tissues, while neurotransmitters travel across the synaptic cleft to transmit signals between neurons. Choice C is incorrect because hormones also act on receptors in target cells, not just neurotransmitters. Both hormones and neurotransmitters can act on specific receptors to elicit a cellular response. Choice D is incorrect because neurotransmitters primarily travel through the synaptic cleft to reach the target cell, while hormones travel through the bloodstream to reach their target tissues.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.