Which of the following hormones plays a key role in the development of the secondary sexual characteristics in the female?

Correct Answer: C

Rationale: The correct answer is C: Oestrogen. Oestrogen is the primary female sex hormone responsible for the development of secondary sexual characteristics such as breast development, regulation of the menstrual cycle, and maintenance of the reproductive system. Adrenaline (A) is a stress hormone that prepares the body for fight or flight responses. Glucagon (B) is a hormone that raises blood sugar levels. Calcitonin (D) is involved in regulating calcium levels in the body. These hormones do not play a direct role in the development of female secondary sexual characteristics.

Correct Answer: A

Rationale: The correct answer is A: short chain fatty acids. Short chain fatty acids are primarily absorbed in the colon through passive diffusion. The colon plays a crucial role in absorbing these fatty acids due to its high concentration of beneficial gut bacteria that break down dietary fiber into short chain fatty acids. Calcium is mainly absorbed in the small intestine, vitamin K is absorbed in the small intestine and partially in the colon, and oligosaccharides are mainly broken down by enzymes in the small intestine.

Correct Answer: D

Rationale: The correct answer is D because blood from the islets of Langerhans drains into the hepatic portal vein. This is important for the regulation of blood glucose levels by allowing insulin and glucagon produced by the islets to reach the liver directly. Choice A is incorrect because D cells secrete somatostatin, not pancreatic polypeptide. Choice B is incorrect as beta cells, not A cells, are the most common in the islets. Choice C is incorrect as the islets are most plentiful in the tail of the pancreas.

Correct Answer: C

Rationale: The correct answer is C because the substrates of the flavoprotein-cytochrome system are pyruvate, water, oxygen, and ATP. Pyruvate is oxidized to produce energy in the form of ATP, water is a byproduct of the electron transport chain, and oxygen is the final electron acceptor. Choices A and B are incorrect because cytochrome oxidase is not the first step in the chain, and the system does not occur within the endoplasmic reticulum. Choice D is incomplete.

Correct Answer: C

Rationale: The correct answer is C because steroid hormones are lipid-soluble and can diffuse through cell membranes. Once inside the cell, they bind to specific receptors in the cytoplasm. This hormone-receptor complex then enters the nucleus to regulate gene expression. Option A is incorrect because steroid hormone receptors are not found on nutrient molecules like glucose. Option B is incorrect as these receptors are not typically located in the interstitial fluid. Option D is also incorrect because steroid hormone receptors are not located on the cell membranes of target tissues.