A student prepared this table to gather information about digestion. Digestion of Food Column A Column B Physical Changes Chemical Changes The results of which investigation would be entered in Column A of the table? A. How do mitochondria release the energy in food molecules? B. Which type of teeth are most important in crushing food? C. What chemicals in the stomach are most important in breaking down proteins? D How do substances released by the pancreas affect the rate of digestion?

B. Which type of teeth are most important in crushing food?

Explanation:

According to the question physical changes ought to be entered into column A while chemical changes ought to be entered into column B.

The crushing of food is a physical change. It does not involve any chemical transformation of the food material.The other options involve some sort of chemical transformation taking place on the food material being digested.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

i'm pretty sure it is letter c.) car