What cellular process ensures the accurate transmission of genetic material during cell division?

Correct Answer: A

Rationale: Mitosis is the correct answer. Mitosis is the process by which somatic cells divide to produce two identical daughter cells. During mitosis, the genetic material is accurately replicated and distributed to ensure each daughter cell receives a complete set of chromosomes. This process is crucial for growth, repair, and maintenance of multicellular organisms. Meiosis, on the other hand, is the type of cell division that occurs in germ cells to produce gametes (sperm and egg cells), focusing on genetic diversity through recombination and reduction of chromosome number. Replication is the process of copying DNA to produce an identical copy, essential for cell division but not the specific process ensuring accurate genetic material transmission. Transcription involves copying DNA into RNA, crucial for gene expression but not directly related to the accurate transmission of genetic material during cell division.

Correct Answer: A

Rationale: As an object falls freely near the Earth's surface, its potential energy decreases. This decrease occurs because the gravitational potential energy is being converted into kinetic energy as the object accelerates due to gravity. According to the law of conservation of energy, the total mechanical energy (the sum of potential and kinetic energy) remains constant in the absence of non-conservative forces like air resistance. Choice B ('Potential energy increases') is incorrect because the object's potential energy is being converted into kinetic energy, leading to a decrease. Choice C ('Potential energy remains constant') is incorrect as the conversion of potential energy to kinetic energy results in a decrease in potential energy. Choice D ('Potential energy becomes zero') is incorrect because potential energy is not reduced to zero but is transformed into kinetic energy as the object falls.

Correct Answer: A

Rationale: Work is done by a force on an object when the object moves in the direction of the force. This is because work is defined as the product of the force applied to an object and the distance over which the force is applied. When the object moves in the direction of the force, the force contributes to the displacement of the object, resulting in work being done. If the object moves perpendicular to the force, no work is done because the force does not contribute to the displacement. Moving against the force also results in work being done as the force is causing the displacement. The vertical movement of the object does not determine whether work is done; it is the alignment of the force with the object's displacement that matters. The duration of force application does not impact whether work is done; as long as the force causes the object to move in its direction, work is being done.

Correct Answer: B

Rationale: The main organ responsible for regulating sleep is the hypothalamus. The hypothalamus plays a crucial role in controlling the body's circadian rhythm, which is the internal clock that regulates the sleep-wake cycle. It receives input from the eyes about light and darkness, aiding in determining when it's time to sleep or wake up. Additionally, the hypothalamus regulates the production of melatonin by the pineal gland, a hormone that helps control sleep patterns. While the thalamus relays sensory information to the brain, the pituitary gland is primarily responsible for hormone production and release, and the pineal gland produces melatonin under the control of the hypothalamus. Therefore, the hypothalamus is the correct choice as the main organ involved in sleep regulation.

Correct Answer: A

Rationale: The correct answer is A: Kidneys. The kidneys are the primary organs responsible for filtering urine. They filter waste products and excess substances from the blood to produce urine. Subsequently, urine travels from the kidneys through the ureters to the bladder. The bladder temporarily stores urine until it is expelled from the body through the urethra. The bladder's function is storage, the ureters transport urine, and the urethra is the exit pathway for urine expulsion. Therefore, the kidneys play a vital role in the filtration and production of urine within the urinary system.