Use arrows and key terms such as "red blood cells," "oxygen," and "EPO" to describe how high-altitude training helps athletes improve their performance at lower altitudes.

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected

Which statement correctly identifies the scientific question and describes why the question is scientific? question 1 refers to the supernatural.question 2 reflects a moral or social value.question 3 refers to something that can be measured.question 4 reflects a question that can’t be observed.

Which is not a characteristic of bacteria? a. they are unicellular. b. they are prokaryotic. c. they are the smallest form of life on earth. d. they are multicellular.