Which of the following structures plays a crucial role in controlling the cell cycle and preventing uncontrolled cell growth?

Correct Answer: A

Rationale: The correct answer is A: The centrioles. Centrioles are cylindrical structures found in animal cells that are crucial in organizing the spindle fibers during cell division (mitosis). They play a vital role in separating chromosomes during cell division, ensuring each daughter cell receives the correct number of chromosomes. Additionally, centrioles are involved in the formation of cilia and flagella, essential for cell motility and sensory functions. The nucleolus is responsible for ribosome production, the Golgi apparatus processes and packages proteins, and the endoplasmic reticulum is involved in protein synthesis and lipid metabolism. These structures do not have a direct role in controlling the cell cycle and preventing uncontrolled cell growth.

Correct Answer: B

Rationale: A) Incorrect. DNA is double-stranded, but RNA is typically single-stranded. B) Correct. DNA contains deoxyribose sugar, which lacks an oxygen atom on the 2' carbon of the sugar ring, while RNA contains ribose sugar, which has an additional hydroxyl group on the 2' carbon. C) Incorrect. RNA contains the nitrogenous base uracil, while DNA contains thymine. D) Incorrect. DNA and RNA have distinct structures and functions, so they are not identical molecules.

Correct Answer: C

Rationale: Citric acid is a weak acid commonly found in citrus fruits like lemons, oranges, and limes. It is responsible for the sour taste in these fruits. Sulfuric acid (option A), hydrochloric acid (option B), and nitric acid (option D) are all strong acids that are typically used in laboratory settings and industrial processes, not naturally found in citrus fruits. Therefore, the correct answer is option C.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: The unit of measurement for force in the International System of Units (SI) is the Newton (N). One Newton is defined as the force required to accelerate a mass of one kilogram at a rate of one meter per second squared. Therefore, the correct answer is Newton (N). The other choices are incorrect because: B) Kilogram (kg) is a unit of mass, not force; C) Joule (J) is a unit of energy; D) Meter per second squared (m/s²) is a unit of acceleration, not force.