What is the significance of studying pedigrees in human genetics?

Correct Answer: B

Rationale: Pedigrees are diagrams that show the relationships within a family and can be used to track the inheritance patterns of specific traits or diseases. While pedigrees can provide information on the inheritance of single gene disorders (such as identifying carriers of dominant genetic disorders, as mentioned in option C), their primary significance lies in studying complex traits with multiple contributing genes. These traits do not follow simple Mendelian inheritance patterns and are influenced by both genetic and environmental factors. By analyzing pedigrees, researchers can identify patterns of inheritance for complex traits, such as polygenic diseases or traits influenced by gene-environment interactions. Therefore, option B is the most appropriate choice as it captures the main significance of studying pedigrees in human genetics.

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.

Correct Answer: C

Rationale: The functional group present in amines is the amine group, represented as -NH2. Amines are organic compounds characterized by the presence of a nitrogen atom bonded to hydrogen atoms. The amine group distinguishes amines from other types of organic compounds, such as alcohols with the hydroxyl group, ketones with the carbonyl group, and nitro compounds with the nitro group. Therefore, the correct answer is 'C: Amine.'