Some fuel cells are powered by hydrogen. scientists are looking into the decomposition of water (h2o) to make hydrogen fuel with the of the sun’s energy. what challenge do scientists face with this task?
a. decomposing water requires a high activation energy.
b. the sun isn't a renewable resource.
c. decomposing water results in toxic byproducts.
d. scientists are uncertain what to do with the excess oxygen.

Which strategy is an example of how companies may upgrade themselves to meet changing customer preferences? a.doing door-to-door sellingb.using billboards to advertise the productsc. making online shopping services availabled.giving discounts on products

Aresearcher designed an investigation to test what effect eating different types of food would have on blood insulin levels. she selected 10 male subjects who were all 25 years of age and in good health. the experiment took place over 3 days. at 8: 00 a.m. on each day, the subjects ate a meal consisting of only 1 type of food. they had their blood insulin levels measured after consuming the meal. on day 1 they ate a high fat diet, on day 2 they ate a high protein diet, and on day 3 they ate a high sugar diel what is the independent variable in this experiment? a the age of the subjects b the blood insulin level c the type of food consumed d the time of day the meal was consumed

What is the next step in the process after a substrate enters the active site of an enzyme