A variety of opossum that lives on an island with no predators lives much longer than its relatives on the mainland, even when both are kept safely in a zoo. The island variant's genes have been selected for slow aging, whereas the mainland variant's genes have been selected for quick reproduction. The island opossum exhibits __________ selection, and the mainland opossum exhibits __________ selection.

• A. r; K
• B. nutrient; territory
• C. iteroparity; semelparity
• D. clumped; uniform
• E. K; r

Answer: (E)

Verified step by step guidance

1. Understand the concept of r-selection and K-selection: r-selection refers to species that reproduce quickly and in large numbers, often in unstable environments. K-selection refers to species that reproduce more slowly and invest more in fewer offspring, often in stable environments.
2. Identify the characteristics of the island opossum: The island opossum lives longer and has genes selected for slow aging, which suggests a stable environment with less pressure to reproduce quickly.
3. Identify the characteristics of the mainland opossum: The mainland opossum has genes selected for quick reproduction, which suggests an unstable environment where rapid reproduction is advantageous.
4. Match the island opossum's characteristics with K-selection: The island opossum's slow aging and longer lifespan are indicative of K-selection, where the focus is on quality and survival of offspring rather than quantity.
5. Match the mainland opossum's characteristics with r-selection: The mainland opossum's quick reproduction aligns with r-selection, where the focus is on producing many offspring quickly to ensure survival in a less stable environment.