Question

1. what role do variations play in evolution?

they are harmful and should be eliminated
they provide the raw material for evolution
they are irrelevant to survival
they only occur in artificial selection

1. what can lead to the extinction of a species?

increased genetic variation
rapid environmental changes
successful reproduction
natural selection

1. what does descent with modification imply?

species do not change over time
all species are identical
species evolve from common ancestors with changes
species only adapt to their current environment

Explanation:

Question 8

In evolution, genetic variations are crucial. They aren't always harmful (some are beneficial or neutral), so the first option is wrong. Variations give the necessary diversity for natural selection to act on, providing the raw material for evolution. They are relevant to survival as they can help organisms adapt, so the third option is wrong. Variations occur in natural populations too, not just artificial selection, so the fourth is wrong.

Increased genetic variation usually helps a species adapt, not lead to extinction. Successful reproduction helps a species thrive. Natural selection is the process that selects beneficial traits, not directly cause extinction. Rapid environmental changes (like climate shifts, habitat destruction) can outpace a species' ability to adapt, leading to extinction.

"Descent with modification" is Darwin's concept. It means species change over time (so first option is wrong), aren't identical (second wrong), and evolve from common ancestors with modifications. The fourth option is wrong as species can adapt to new environments too, not just current.

Answer:

B. They provide the raw material for evolution

Question 9