Correct Answer: D

Rationale: Both metabolic and respiratory alkalosis can cause overexcitability and nervous system stimulation due to a decrease in ionized calcium levels, which can cause symptoms such as tetany and paresthesias. Acidosis typically has the opposite effect, leading to depression of the nervous system.

Correct Answer: A

Rationale: The correct answer is A: A white reflex. The 'white reflex' or leukocoria is a common sign of retinoblastoma. It occurs when the light reflects off the tumor in the eye, giving the pupil a white appearance instead of the normal red reflex. Blue-tinged sclerae (choice B) and yellow-tinged sclerae (choice D) are not typical manifestations of retinoblastoma. A red reflex (choice C) is the normal reflection seen in the eye when light is shone on it and is not associated with retinoblastoma.

Correct Answer: D

Rationale: Both metabolic and respiratory alkalosis can cause overexcitability and nervous system stimulation due to a decrease in ionized calcium levels, which can cause symptoms such as tetany and paresthesias. Acidosis typically has the opposite effect, leading to depression of the nervous system.

Correct Answer: D

Rationale: The correct answer is D: Hypertension. Nephroblastoma, also known as Wilms' tumor, often causes hypertension due to its impact on the kidney, which plays a role in regulating blood pressure. Atrial fibrillation (choice A) and endocarditis (choice B) are not typically associated with nephroblastoma. Hyperlipidemia (choice C) is also not a common clinical manifestation of nephroblastoma.

Correct Answer: A

Rationale: Picking up a pencil requires the use of the pincer grasp, which involves the coordination of the thumb and forefinger to hold small objects. The pincer grasp is a fine motor skill essential for tasks that necessitate precision and dexterity. Choices B, C, and D are incorrect. Prehension refers to the act of grasping or holding an object, parachute reflex is a protective response to sudden movement or loss of support, and grasp reflex is an automatic closing of the hand when an object is placed in the palm, none of which specifically relate to the action of picking up a pencil.