Correct Answer: D

Rationale: The correct answer is D: T4. The primary hormone secreted by the thyroid gland is thyroxine, also known as T4. T4 plays a crucial role in regulating metabolism, growth, and energy levels in the body. It is converted into the more active form, triiodothyronine (T3), which exerts most of the biological effects of thyroid hormones. Choices A, B, and C are incorrect. Oxytocin is not produced by the thyroid gland but by the pituitary gland, TSH (thyroid-stimulating hormone) is secreted by the pituitary gland to stimulate the thyroid gland, and adrenaline is produced by the adrenal glands, not the thyroid gland.

Correct Answer: D

Rationale: The correct answer is D because the urinary system eliminates some waste products of digestion. After digestion in the digestive system, nutrients are absorbed into the bloodstream, and waste products are transported to the kidneys via the urinary system to be excreted as urine. This process helps eliminate waste products generated during digestion, illustrating the coordination between the digestive and urinary systems. Choices A, B, and C are incorrect. Choice A is incorrect as the ureter is part of the urinary system, not controlled by the digestive system. Choice B is incorrect as the urinary system primarily removes metabolic waste, not toxins from digestion. Choice C is incorrect because the digestive system mainly aids in digestion and nutrient absorption, not hormone production affecting urination.

Correct Answer: A

Rationale: Hormones are signaling molecules produced by glands in multicellular organisms. They travel through the bloodstream to specific target cells where they regulate various physiological processes, including growth, differentiation, and metabolism. Neurons (choice B) are nerve cells that transmit nerve impulses and are not responsible for controlling growth, differentiation, or metabolism. Glands (choice C) produce and release hormones but are not the chemical messengers themselves. Second messengers (choice D) are molecules involved in intracellular signal transduction, not the primary chemical messengers controlling growth, differentiation, and metabolism. Therefore, hormones (choice A) are the correct answer as they match the description provided in the question.

Correct Answer: D

Rationale: The correct answer is D: Nervous system. The nervous system is primarily responsible for integrating voluntary movements. This system includes the brain, spinal cord, and peripheral nerves that communicate signals throughout the body to control movement. The brain interprets sensory information, formulates decisions, and sends signals to the muscles to execute voluntary movements. The cardiovascular system is responsible for circulating blood, the digestive system for breaking down food and absorbing nutrients, and the respiratory system for gas exchange in the body. Choices A, B, and C are incorrect as they do not play a primary role in integrating voluntary movements.

Correct Answer: D

Rationale: The correct answer is D: A cut through the transverse plane. A transverse plane cut, also known as a cross-section, divides the body or an organ into superior and inferior portions. This type of cut is perpendicular to the long axis of the body and is commonly used in medical imaging to display internal structures and organs in a horizontal view. Choices A, B, and C are incorrect because a sagittal or frontal section (A) divides the body into left and right portions, a cut along the coronal plane (B) separates the body into anterior and posterior parts, and a cut along the median plane (C) divides the body into equal left and right halves.