Is mixing sand a gravel a physical or chemical change?

What is one benefit of a nonrenewable resource, such as natural gas? a. generate large amounts of electricity b. less expensive overtime c. produces pollution d. will run out eventually

How had the study of mitosis affected scientists knowledge of cancer

The seed coat's most important function is to provide a) a nonstressful environment for the megasporangium. b) the means for dispersal. c) dormancy. d) a nutrient supply for the embryo. e) desiccation resistance.