Correct Answer: A

Rationale: Nitrogen is the most abundant gas in Earth's atmosphere, constituting approximately 78% of the air we breathe. It is essential for various biological processes, including plant growth and nitrogen fixation. Moreover, nitrogen is a key component of the greenhouse effect, playing a crucial role in regulating the planet's temperature. Oxygen, while important for respiration, comprises about 21% of the atmosphere. Carbon dioxide, though vital for photosynthesis and a greenhouse gas, is present in much lower concentrations than nitrogen. Argon, an inert gas, is a minor component of the atmosphere.

Correct Answer: B

Rationale: The correct answer is B because if an object is initially at rest and no force is acting on it, it will remain at rest due to Newton's First Law of Motion. This law states that an object at rest will stay at rest unless acted upon by an external force. Choices A, C, and D all involve forces acting on the object, which would cause it to move according to Newton's laws of motion. Choice A, a constant force acting on the object, would cause it to move at a constant velocity. Choice C, a force that increases in magnitude over time, would accelerate the object. Choice D, a force that decreases in magnitude over time, would decelerate the object.

Correct Answer: D

Rationale: The distribution of organisms geographically is influenced by various factors. The availability of specific types of food sources is crucial as organisms need suitable food sources to survive and thrive in an area. Tolerance of organisms to different temperature ranges is also important, as temperature impacts where species can live. Organisms must withstand temperature conditions to survive. Competition for mates within the same species affects population sizes and dynamics in different areas. Therefore, all these factors collectively influence the distribution of organisms geographically. Choice D, 'All of the above,' is the correct answer because each of the factors mentioned (availability of food sources, tolerance to temperature ranges, and competition for mates) plays a significant role in determining the distribution of organisms in different geographical locations. Choices A, B, and C are incorrect because they each only represent one specific factor that influences distribution, whereas the correct answer encompasses all the major factors mentioned.

Correct Answer: A

Rationale: Mitosis is a type of cell division specific to eukaryotic cells that results in the production of two identical daughter cells, each with the same genetic material as the parent cell. This process is crucial for growth, tissue repair, and maintaining a constant number of chromosomes in multicellular organisms. During mitosis, the replicated chromosomes are segregated into two separate nuclei, followed by the division of the cell into two identical daughter cells. Options B, C, and D are incorrect as mitosis does not lead to the production of four haploid cells, a single diploid cell, or a single haploid cell. The correct answer is A because mitosis results in the formation of two daughter cells that are genetically identical to each other and to the parent cell, allowing for growth and replacement of damaged cells in multicellular organisms.

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.