Ascientist tries to mate the two similar-looking fruit flies drosophila melanogaster and drosophila simulans. but he finds that they are unable to produce viable offspring. what kind of evolutionary barrier could this be?

(drag each tile to the correct location.) categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. - a tentative statement used to guide scientific investigations. - makes predictions about future events. - can be tested by many independent researchers. - based on observations of natural phenomena. - a well-established, highly reliable explanation.

18. which statement about cancer is true?

We can be sure that a mole of table sugar and a mole of vitamin c are equal in their 1) mass in daltons. 2) mass in grams. 3) number of molecules. 4) number of atoms. 5) volume.