Read the passage about genetic diversity in black rhinoceros populations, and then answer: genetic diversity is directly proportional to which of the following?

Introduction / Context:
This question is again built on the same passage about black rhinoceros but now focuses on the relationship between genetic diversity and other biological outcomes. The author explains that low genetic diversity decreases the ability of a species to survive and reproduce. Therefore, high genetic diversity supports better survival and reproduction. Questions like this test your understanding of cause and effect relationships as described in the text, rather than only your raw memory of numbers or names.

Given Data / Assumptions:
• The passage states that genetic variation is the cornerstone of evolution. • It clarifies that without genetic variation there can be no natural selection. • It explicitly says that low genetic diversity decreases the ability of a species to survive and reproduce. • From this logic, higher genetic diversity improves the ability of a species to survive and reproduce.

Concept / Approach:
The concept here is proportionality. If low genetic diversity harms survival and reproduction, then high genetic diversity should support them. You can think of genetic diversity and the ability to survive and reproduce as moving in the same direction. The more diverse the gene pool, the better the chances that some individuals will tolerate diseases, environmental changes, and other stresses. In exam terms, you must pick the option that summarises this positive relationship, not one that describes an inverse or unrelated link.

Step-by-Step Solution:
1. Recall from the passage that "a low genetic diversity decreases the ability of a species to survive and reproduce". 2. Translate this into proportional language: as genetic diversity decreases, ability to survive and reproduce decreases. 3. Therefore, as genetic diversity increases, the ability to survive and reproduce increases. 4. Check the options and identify which one describes this supportive or positive relationship. 5. Option B mentions "the ability of a species to survive and reproduce", which matches the passage. 6. Confirm that no other option correctly expresses this same positive proportional relationship.

Verification / Alternative check:
To verify, imagine two species: one with very high genetic diversity and one with extremely low diversity. The species with high diversity should be more adaptable and resilient, whereas the one with low diversity is more vulnerable to disease and environmental change. This thought experiment fits perfectly with the passage. When you link this reasoning back to the options, only option B fits both the passage and general biological understanding, making it a reliable choice.

Why Other Options Are Wrong:
Option A, species population size alone, is not always directly proportional to genetic diversity, because a large but inbred population may still have low diversity. Option C, the degree of inbreeding, generally moves in the opposite direction: high inbreeding usually reduces genetic diversity. Option D, the risk of extinction, is inversely related: as genetic diversity decreases, extinction risk increases, so they do not rise or fall together. None of these alternatives correctly describe the direct positive proportional link described by the passage.

Common Pitfalls:
Some learners confuse correlation and causation or fail to notice whether two factors move in the same or opposite directions. Others may try to reason from general ideas rather than returning to the exact sentence in the passage. A safer method is to rewrite the key sentence from the passage in your own words and then match that restated idea with the options. Doing so helps prevent you from being distracted by plausible but incorrect statements about population size or extinction risk.

Final Answer:
Genetic diversity is directly proportional to the ability of a species to survive and reproduce.