Correct Answer: B

Rationale: The correct answer is B: P wave, QRS complex, T wave. The components of an ECG include the P wave (atrial depolarization), QRS complex (ventricular depolarization), and T wave (ventricular repolarization). The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. Options A, C, and D have incorrect combinations of ECG components. Option A incorrectly includes the U wave, which is not a standard component of a typical ECG. Option C includes the S wave, which is not a primary component of a standard ECG. Option D includes the U wave, which is not a standard component, and the S wave, which is not a primary component of an ECG. Therefore, option B is the most accurate combination of components for an ECG.

Correct Answer: B

Rationale: The correct answer is B: Insulin. Insulin is produced by the pancreas and plays a crucial role in lowering blood sugar levels by promoting the uptake of glucose into cells for energy production or storage. Glucagon, which is also produced by the pancreas, functions to increase blood sugar levels by stimulating the release of stored glucose. Adrenaline, produced by the adrenal glands, is involved in the fight-or-flight response and does not directly regulate blood sugar levels. Melatonin, produced by the pineal gland, primarily regulates the sleep-wake cycle and is not involved in blood sugar level control.

Correct Answer: B

Rationale: The correct answer is B, Skeletal muscle. Skeletal muscle is both voluntary and striated, as well as attached to bones, allowing for movement. Smooth muscle, on the other hand, is involuntary and typically found in the walls of internal organs, controlling functions like digestion. Cardiac muscle is also striated, but it is involuntary and specifically found in the heart, responsible for cardiac contractions to pump blood. 'Epithelial muscle' is an incorrect term; epithelial tissue is a type of tissue that forms the linings of various body surfaces and structures, not a muscle type.

Correct Answer: C

Rationale: The correct answer is C. The ovaries are responsible for producing eggs (ova) and hormones (estrogen and progesterone). They are essential for reproduction, including the release of eggs for fertilization and for regulating the menstrual cycle. The fallopian tubes, as mentioned in choice A, transport eggs from the ovaries to the uterus for potential fertilization. The vagina, described in choice B, serves as the birth canal and also connects the uterus to the external environment. The cervix, as stated in choice D, is the lower part of the uterus that connects it to the vagina and also plays a role in protecting the uterus from infections and serving as a passage for menstrual flow.

Correct Answer: B

Rationale: The correct answer is B. Mitosis occurs in somatic cells where a single cell divides to produce two identical daughter cells. Germ cells undergo meiosis, not mitosis. Choice C is incorrect as mitosis results in the preservation of the same chromosome number in daughter cells. Choice D is inaccurate as mitosis produces genetically identical cells, not genetically different ones.