Which Technique Has Been Shown to Be Most Successful at Extending

question 82

Multiple Choice

Which technique has been shown to be most successful at extending life in laboratory animals?

• A)Severe calorie restriction
• B)Manipulation of a gene on the 21st chromosome
• C)Hormone replacement therapy
• D)Injections of free radicals

---

Definitions:

Food Chain

The series of organisms through which energy flows in an ecosystem. Each organism in the series eats or decomposes the preceding organism in the chain.

Competitive Exclusion

A principle stating that two species competing for the same limiting resources cannot coexist at constant population values.

Character Displacement

The phenomenon where differences among similar species whose distributions overlap geographically are accentuated in regions where the species co-occur, but are minimized or lost where the species' distributions do not overlap.

Primary Succession

An ecological succession that occurs on land that has not previously been inhabited by plants; no soil is present initially. See succession. Compare with secondary succession.