Correct Answer: B

Rationale: Smooth muscle is the correct answer. It is found in the walls of hollow organs like the stomach and intestines, where it performs involuntary contractions to move substances through these organs. Cardiac muscle, found in the heart, is responsible for pumping blood. Skeletal muscle is attached to bones and involved in voluntary movements. Striated muscle is a term often used interchangeably with skeletal muscle, which is responsible for voluntary movements but not typically found in the walls of hollow organs like the stomach and intestines.

Correct Answer: B

Rationale: The correct answer is the dermis. The dermis is the deeper layer of the skin that contains connective tissue, blood vessels, and nerve endings. It is located beneath the epidermis and provides structural support, nourishment, and sensitivity to the skin. The epidermis is the outermost layer of the skin responsible for protection. The hypodermis, also known as the subcutaneous layer, is the deepest layer that contains fat cells and plays a role in insulation and energy storage. The stratum corneum is the outermost layer of the epidermis composed of dead skin cells that are continually shed and replaced.

Correct Answer: A

Rationale: The correct answer is the cerebellum. It plays a vital role in balance and coordination by controlling motor functions, precision, and timing of movements. The cerebrum is primarily involved in higher brain functions such as thinking and problem-solving. The hypothalamus regulates essential bodily functions like temperature and hunger, while the thalamus serves as a relay station for sensory information, directing it to the appropriate areas of the brain for processing.

Correct Answer: A

Rationale: Rationale: - Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, one from each parent. While they carry the same genes, they may have different alleles (variants of a gene). - Sister chromatids are exact copies of each other, formed during DNA replication. They are held together by a centromere and are produced during the S phase of the cell cycle. - During meiosis, homologous chromosomes pair up and exchange genetic material through crossing over, leading to genetic variation. Sister chromatids separate during mitosis to ensure each daughter cell receives an identical copy of the genetic material.

Correct Answer: B

Rationale: Friction is a force that opposes motion when two surfaces are in contact. It acts in the opposite direction to the direction of motion, causing objects to slow down or come to a stop. Therefore, friction decreases speed rather than increasing it. Choice A is incorrect as friction does not increase speed but rather hinders it. Choice C is incorrect because friction does have an impact on speed by slowing down objects. Choice D is incorrect as friction's effect is not making objects float but rather causing resistance to motion.