What was the student’s independent variable? A. The amount of salt added to the extraction sample
B. The type of sample from which DNA was extracted
C. The mass of DNA collected from samples
D. The size (mass) of the sample being tested

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

Will mark brainliest. (20 points) many have pigments structures known as eyespots that detect direction of light. a. b. archaebacteria c. protists d. none of the above