What is the function of ribosomal RNA (rRNA)?

Correct Answer: C

Rationale: Ribosomal RNA (rRNA) plays a crucial role in forming the structural framework of ribosomes. Ribosomes are the cellular organelles responsible for protein synthesis and consist of both protein and rRNA components. The primary function of rRNA is to provide the structural support necessary for ribosomes to function properly. This structural framework allows the ribosome to interact with messenger RNA (mRNA) and transfer RNA (tRNA) during translation, where genetic information encoded in mRNA is used to assemble proteins from amino acids. Therefore, rRNA's main role is in contributing to the structure and function of ribosomes, rather than directly carrying amino acids, reading the genetic code, or controlling the rate of protein synthesis. Choices A, B, and D are incorrect because rRNA does not carry amino acids to the ribosomes (tRNA does this), read the genetic code (this is the role of ribosomes and tRNA), or control the rate of protein synthesis (this is regulated by various factors but not directly by rRNA).

Correct Answer: A

Rationale: Newton's third law of motion states that for every action, there is an equal and opposite reaction. This law emphasizes that forces always exist in pairs. When one object exerts a force on a second object (action), the second object exerts an equal force in the opposite direction back on the first object (reaction). This principle is crucial in understanding the interactions between objects and the resulting motion observed in the physical world. Choices B, C, and D are incorrect because while force is involved, the specific concept highlighted by Newton's third law is the equal and opposite reaction. Acceleration and momentum are also related to motion but are not directly tied to Newton's third law of motion, which focuses on the equality and oppositeness of forces in interactions.

Correct Answer: A

Rationale: An increase in surface area typically increases the force of friction between two surfaces. This is because with a larger surface area in contact, there are more points of contact between the surfaces, leading to a greater frictional force resisting motion. As a result, the correct answer is that an increase in surface area increases the force of friction between two surfaces. Choice B is incorrect because a greater surface area increases the frictional force. Choice C is incorrect because an increase in surface area results in more contact points and greater friction. Choice D is incorrect as the relationship between surface area and friction is predictable - an increase in surface area generally leads to an increase in frictional force.

Correct Answer: A

Rationale: Mass is a measure of inertia. Inertia is the resistance of an object to changes in its state of motion, and mass quantifies this resistance. Objects with more mass have greater inertia, meaning they are more resistant to changes in their motion. Therefore, mass and inertia are directly related, with mass being a fundamental factor that determines the level of inertia an object possesses. Choice B is incorrect because mass and inertia are indeed related. Choice C is incorrect as inertia is not a measure of weight but rather a property related to an object's mass. Choice D is incorrect because inertia actually increases with increasing mass, not decreasing mass.

Correct Answer: B

Rationale: According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When you push against a wall with a certain force, the wall will push back on you with an equal force in the opposite direction. Choice A is incorrect because the wall exerts an equal force back. Choice C is incorrect as it suggests a greater force, which goes against Newton's third law. Choice D is incorrect as the wall does exert a force back in response to your push.