if dna of a particular species was analyzed and it was found that it contains 21 percent a, what would be the percentage of c?

Ageologist determines that a sample of a mineral cant be scratched by a steel nail but can be scratched by a masonry drill bit based on this information the sample mineral has to be softer than

Sediment layers stop lateral spreading when: they encounter a barrier they encounter an opposing current they run out of additional sedimentary material

List five ways we are indebted to phytoplankton