One advantage of experiments is that they a. can be difficult to design  b. are often realistic  c. allow cause and effect to be considered  d. can be affected by human error

Answer – C.

One advantage of experiments is that they allow cause and effect to be considered. The freedom to manipulate variables in experiments gives researchers the ability to observe and examine various cause and effect relationships that can be produced by a product, theory, or idea.

answer; i believe the answer is hydraulic action;

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.