Greg and andrea are trying to find out how long it takes amylase, a digestive enzyme found in saliva, to break down a sample of starch. they put their sample in a beaker and covered it with their own saliva. after allowing it to sit on the lab table for 1 hour they measured the remaining surface area of the starch. what is the best way they could improve their experiment? a. take consistent amounts of their saliva samples with varying amounts of starch b. take consistent amounts of saliva samples and consistent amounts of starch c. take varying amounts of saliva samples and a consistent amount of starch d. take varying amounts of saliva samples and varying amounts of starch

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

The same agricultural practices are used in every country of the world. select the best answer from the choices provided t f