Why is this a scientific question? “do people perform better on exams when they wear their favorite color? ”
a. the question is not specific.
b. the question reflects an opinion.
c. the question can be tested by a systematic procedure.
d. the question asks about phenomena that cannot be measured.

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

All annelids and arthropods have a blank body plan . unlike annelids, arthropods also have blank . the circulatory system of annelids is blank , while circulatory system of arthropods is blank .

According to the article, what valid claim came from the national research council? there is no association between fluoride exposure and increased cancer risk in humans. there is a possible link between fluoride exposure and increased cancer risk in humans. there is a definite link between fluoride exposure and increased cancer risk in humans.