Ethanol is a chemical that can be synthetically produced from the sugars of plants, such as corn, using the fermentation reaction shown below. The reaction shows that sugar from plants can be broken down into ethanol and carbon dioxide, releasing heat.

sugar → ethanol + carbon dioxide + heat

In the United States, the sugar used to produce ethanol is commonly gained from corn—the same type of corn that is used for some foods, like corn flour, corn syrup, and corn oil. The ethanol can then be used as fuel in automobiles.

Scientists and engineers are working to develop ways to replace corn with a different plant, such as switchgrass, in the production of ethanol. This is largely because using corn to produce ethanol could cause a problem for society. Which statement describes this problem?
A.
Chemical processes that can transform corn's sugars into ethanol do not exist.
B.
Grass resources are scarce and could be used up if harvested to produce ethanol.
C.
Chemical processes that can release the chemical energy in ethanol do not exist.
D.
Corn grown for ethanol could take up field space that had been used to grow corn for food.

Bisphenol a (often called bpa) is a chemical found in products that people use every day, from water bottles to food containers to children's toys. unfortunately, bpa leaches out of its many products and makes its way into our bodies. what are the health effects of bpa exposure? ongoing research is finding that elevated exposure to bpa can affect a wide variety of developmental and physiological processes, but one of the first studies of bpa's health effects came about because of a simple mistake in the lab. at a laboratory at case western reserve university in 1998, geneticist patricia hunt was making a routine check of her female lab mice. as she extracted and examined developing eggs from the ovaries, she began to wonder what had gone wrong. she noticed that many of the eggs showed problems with their chromosomes, and some had irregular amounts of genetic material, which can lead to miscarriages and birth defects in mammals. she learned that a lab assistant had mistakenly washed the plastic mouse cages and water bottles with a harsh soap, releasing bpa from the plastic. knowing that bpa is an endocrine disruptor, a chemical that can enter organisms and mimic hormones, hunt set out to discover whether it had adversely affected her mice.

In this experiment, the was intentionally manipulated. it is the independent variable. the dependent variables that were measured were the

Which of these statements is true about autotrophs, but not heterotrophs? a. they use sugar and oxygen to make carbon dioxide and water.b. they use chlorophyll and oxygen to make carbon dioxide and water.c. they use sunlight, water, and carbon dioxide to make sugars.d. they use sunlight, water, and oxygen to make chlorophyll.