1) А.
What limits what scientists can study in their work?
They can study only phenomena that they can observe or model.
They can study only the events that take place on Earth.
They can investigate only questions that they were the first to ask.
B.
C.
D.
They can investigate only the areas of science in which they are experts.

Which is an example of a population?

How are the reproductive cycles of a fungus and a pteridophyte similar? a)both organisms form fruiting bodies that produce diploid seeds. b)both organisms produce haploid spores and exhibit diploid and haploid stages. c)both organisms reproduce sexually when two haploid hyphae fuse. d)both organisms exhibit a diploid stage and are only able to reproduce asexually.

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere