Question

the traits of individuals best adapted to survive become more common in each new generation because
offspring without those traits do not survive.
organisms with those traits are more likely to survive and reproduce.
those individuals do not breed.
natural selection does not affect well - adapted individuals.
which of the following best describes random changes in the genetic composition of a population over many generations?
mutation
evolution
emigration
biomagnification

Explanation:

First Question (About Traits in Generations)

To solve this, we analyze each option:

• Option 1: Offspring without adaptive traits may still survive (not all die), so this is incorrect.
• Option 2: Organisms with adaptive traits have higher survival and reproduction rates, passing traits to next generations. This matches natural selection.
• Option 3: If individuals with adaptive traits don't breed, their traits won't spread, which contradicts the question's premise.
• Option 4: Natural selection acts on all individuals, including well - adapted ones (e.g., competition for resources), so this is wrong.

Analyze each option:

• Option 1: Mutation is a random change in DNA. Over generations, accumulated mutations can change a population's genetic composition.
• Option 2: Evolution is the change in genetic composition over time, but it's a broader term. The question specifies "random changes", and mutation is the source of random genetic variation.
• Option 3: Emigration is movement of individuals out of a population, affecting population size, not random genetic composition change.
• Option 4: Biomagnification is about toxin accumulation in food chains, not genetic changes.

Answer:

B. organisms with those traits are more likely to survive and reproduce.

Second Question (About Random Genetic Changes)