What is the approximate composition of the air in the balloons?

Correct Answer: C

Rationale: The correct answer is C (21, 0.04, high). This composition represents the approximate percentage of oxygen (21%) and carbon dioxide (0.04%) in the air inside the balloons. Oxygen is a major component of the air we breathe, making up around 21% of the atmosphere. Carbon dioxide, on the other hand, is present in trace amounts, about 0.04%. The other choices are incorrect because they do not accurately represent the typical composition of air. Choice A has a low oxygen content and choice B has a high carbon dioxide content, both of which do not align with the usual composition of the air. Choice D also has a low oxygen content and high carbon dioxide content, making it incorrect.

Correct Answer: D

Rationale: The correct answer is D: 600 cm/s. The speed of a wave is determined by the formula speed = frequency x wavelength. Given that the frequency and wavelength are constant, the only way to increase the speed is to increase the frequency or the wavelength. Since both frequency and wavelength are fixed, the speed can only be increased by increasing both. Choice D, 600 cm/s, is double the speed of choice C, 300 cm/s, which indicates that both frequency and wavelength have been doubled, leading to the correct answer. Choices A and B are too low to be correct, as they are not consistent with the principles of wave speed calculation.

Correct Answer: B

Rationale: The correct answer is B: steroid hormones. Steroid hormones are known to regulate gene expression by binding to specific receptors and influencing transcription processes. They can directly affect the transcription of new messenger RNA in the cell. Pancreatic hormones (A), catecholamines (C), and pituitary gland hormones (D) are not directly involved in the transcription of new messenger RNA. Pancreatic hormones primarily regulate blood sugar levels, catecholamines are involved in the fight-or-flight response, and pituitary gland hormones regulate various functions such as growth, reproduction, and metabolism.

Correct Answer: B

Rationale: Excess growth hormone suppresses cancer by promoting healthy cell growth and inhibiting apoptosis. Diabetes can result from growth hormone excess due to insulin resistance. Giantism in children and acromegaly in adults are both caused by excess growth hormone stimulating excessive skeletal and soft tissue growth. Therefore, the correct answer is B because excess growth hormone does not suppress cancer; it actually promotes cell growth and proliferation.

Correct Answer: A

Rationale: Step 1: The pituitary gland is located in the sella turcica of the sphenoid bone. Step 2: The cavernous sinus is a venous sinus located on each side of the sella turcica. Step 3: The pituitary gland lies laterally to the cavernous sinus. Step 4: Therefore, the correct answer is A: The cavernous sinus. Summary: B is incorrect as the hypothalamus is superior to the pituitary gland. C is incorrect as the diaphragma sellae is a part of the dura mater covering the pituitary gland. D is incorrect as the optic chiasma is located superior to the pituitary gland.