Correct Answer: C

Rationale: When there is no external force acting upon an object, the law of conservation of momentum dictates that the momentum of the object remains constant. This means that the momentum does not increase or decrease; it stays the same.
Choice A is incorrect because momentum does not increase.
Choice B is incorrect because momentum does not decrease.
Choice D is incorrect as momentum does not become zero; it remains constant as per the conservation law.
Therefore, the correct answer is C, as the object's momentum is unchanged in the absence of external forces.

Correct Answer: C

Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums.
Therefore, the correct answer is the change in wave speed (
Choice
C).

Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed.
Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.

Correct Answer: B

Rationale: The correct answer is B: Prokaryotic cell. Prokaryotic cells are characterized by having a nucleus that is not enclosed within a membrane (nuclear envelope) and lacking membrane-bound organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus. Plant, animal, and fungal cells are eukaryotic cells, which have a true nucleus enclosed within a nuclear envelope and contain membrane-bound organelles.
Therefore, options A, C, and D are incorrect as they all represent eukaryotic cells that possess membrane-bound organelles.

Correct Answer: B

Rationale: Translation is the correct answer. It is the process of converting the information in mRNA into a sequence of amino acids to form a protein. Transcription (
Choice
A) is the process of copying a segment of DNA into RNA. Replication (
Choice
C) is the process of making an identical copy of DNA. Mutation (
Choice
D) refers to a change in the DNA sequence that can lead to variations in proteins, but it is not the process of converting DNA into a protein.

Correct Answer: B

Rationale: A concentrated solution of a strong electrolyte is most likely to conduct electricity well. Strong electrolytes completely dissociate into ions in solution, allowing for the flow of electric current. This high concentration of ions in the solution enhances its conductivity, making it a better conductor compared to other options. A saturated solution, although containing dissolved ions, may not have a high enough concentration to conduct electricity effectively. A dilute solution of a weak acid is a poor conductor as weak acids only partially dissociate into ions. A mixture of a neutral compound and water does not contain free ions necessary for conducting electricity.