Why is it necessary that only one variable be changed in an experiment,
and that all other variables remain constant?

Identify the main component f natural gas

Which of the following statements is true? a. the main cause for speciation is an increase in gene flow. b. organisms that reproduce asexually are not considered part of a species. c. on a tree of life diagram, speciation is shown by the merging of two different lineages. d. the size of the geographic area inhabited by a population can cause speciation.

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.