Question

what makes climate change research valid?
a. most climate change studies are by unknown scientists.

b. only a few scientists believe climate change is occurring.

c. many lines of evidence show climate change occurring.

d. most climate change studies show variability in opinion.

Explanation:

• Option A: Valid research isn't determined by scientists' fame; unknown scientists can still do valid work, but this doesn't make research valid. Eliminate A.
• Option B: The scientific consensus is that most scientists accept climate change is occurring, so "only a few" is incorrect. Eliminate B.
• Option C: In science, multiple independent lines of evidence (e.g., temperature records, ice core data, sea - level rise) supporting a phenomenon (climate change here) is a key to valid research. This option is correct.
• Option D: Variability in opinion doesn't equate to validity. Valid research is based on evidence, not opinion variability. Eliminate D.

Answer:

C. Many lines of evidence show climate change occurring.