Correct Answer: B

Rationale: The correct answer is B. CRISPR-Cas9 technology allows precise editing of germline cells, raising ethical concerns about modifying the human gene pool. This includes potential eugenic implications, debates on altering future generations, and the moral implications of such genetic modifications. Choice A discusses unintended consequences and off-target effects, but the primary ethical consideration with CRISPR-Cas9 technology relates to altering the human germline. Choices C and D, while important factors, are not the central ethical dilemmas associated with using CRISPR-Cas9 technology in humans.

Correct Answer: B

Rationale: The number of protons in an atom is known as the atomic number. The atomic number uniquely identifies an element and determines its position on the periodic table. It is a fundamental property of an element and directly influences its chemical behavior and interactions. The mass number, on the other hand, is the sum of protons and neutrons in the nucleus of an atom, not just protons. Atomic weight is the average mass of an element's isotopes considering their relative abundance, not solely based on the number of protons. Valence electron count refers to the number of electrons in the outermost energy level of an atom, influencing its ability to form bonds and participate in chemical reactions, but it is not determined by the number of protons in the atom.

Correct Answer: D

Rationale: Rationale: A) Mutations in genes: Mutations are changes in the DNA sequence that can introduce new alleles into a population, leading to genetic variation. B) Genetic drift (random fluctuations in allele frequencies): Genetic drift refers to random changes in allele frequencies in a population, which can lead to genetic variation through chance events. C) Gene flow (movement of genes between populations): Gene flow occurs when individuals move between populations, bringing new alleles with them and increasing genetic variation within populations. D) Blending inheritance (traits of parents are averaged in offspring): Blending inheritance was a historical theory that suggested offspring inherit a blend of traits from their parents, leading to a reduction in genetic variation over time. However, this concept has been disproven by the understanding of Mendelian genetics, where traits are inherited independently and do not blend together. Therefore, blending inheritance does not contribute

Correct Answer: D

Rationale: Work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. This means that work is only done when the force and displacement are in the same direction. If the force and displacement are not in the same direction, only the component of the force in the direction of the displacement contributes to the work done. Therefore, choice D correctly defines work in terms of force and displacement. Choices A, B, and C are incorrect because work is specifically calculated based on the force and displacement in the direction of the force, not in any direction, only when the displacement is vertical, or when the force and displacement are perpendicular.

Correct Answer: C

Rationale: Inertia is an object's resistance to a change in its state of motion, as described by Newton's first law. This means that an object will maintain its current state, whether it is stationary or moving at a constant velocity, unless it experiences an external force. Choices A and B illustrate specific instances of inertia where objects in motion or at rest continue as such without external interference. Option D refers to the force necessary to elevate an object, which is not directly linked to the concept of inertia.