Which of the following blood cells helps in blood cloting? 1.RBC 2.WBC 3.Platelets 4.Other

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

All organisms contribute some water to the water cycle by conducting

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.