Which best explains why muscle cells have more mitochondria than skin cells? A
Muscle cells divide more often than skin cells.
B
Muscle cells make more protein than skin cells.
C
Muscle cells require more energy than skin cells.
D
Muscle cells break down more waste than skin cells.

Tara sees a commercial for a brand of pills that promise to boost energy and people perform better in work and school. as people in the commercial talk about how much better they feel when taking the pill, tara notices a message on the bottom of the screen that reads, "this pill is not approved by doctors and has not been tested in controlled experiments." what is the best conclusion that tara should make about the commercial? it is making scientific claims based on subjective observations. it is making scientific claims based on opinions instead of pseudoscientific facts. it is making pseudoscientific claims based on objective observations. it is making pseudoscientific claims based on opinions instead of scientific facts.

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a. one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b. one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c. one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm