Question: In the geologic past, abiotic factors such as volcanic eruptions have had an impact on the availability of resources. How can volcanic eruptions impact the availability of resources?

  Options: 
 A. by decreasing the thickness of soil
 B. by causing more heavy rains to erode topsoil
 C. by disrupting the sunlight from reaching producers
 D. by causing the surface of Earth to be warmer than usual 
Answer: C