Read the passage and mark the letter A, B,...

Câu hỏi: Read the passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions. 

A. no one understands how to apply gravitational science.

B. dark matter has little effect on surrounding matter.

C. dark matter cannot be directly observed.

D. there is absolutely no evidence for the existence of dark matter.