In a uranium fission reaction, uranium splits into two smaller atoms and energy. where did the energy come from? a. chemical bonds are broken, and chemical energy is released. b. when the uranium splits, mass and energy are created making the two new atoms. c. some of uranium's mass is converted into energy, so the smaller atoms have less mass. d. the energy had to be the kinetic energy of the atom of uranium before it split.

Some of uranium's mass is converted into energy, so the smaller atoms have less mass.

The answer is C-

Some of uranium's mass is converted into energy, so the smaller atoms have less mass.

Explanation:

In Uranium fission reaction, a neutron collides uranium atom splitting into smaller atoms and energy, some of uranium's mass is converted into energy, so the smaller atoms have less mass.

The process keep repeating itself again and again.

I hope this helps.

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.