Which is an example of positive phototropism?
a: plant root growing down into the soil
b: plant root growing up out of soil
c: plant shoot growing down into the soil
d: plant shoot growing up out of soil

Which part of the spine is likely to cause a nerve signal to travel faster? a. backbones b. white matter c. nuclei d. gray matter

Tay-sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. which cellular organelle must be involved in this condition?

Which of the following correctly matches an immune system cell with the defense it produces? a. b cells release cytotoxins. b. t cells release cytotoxins. c. b cells absorb antibodies. d. t cells absorb antibodies.