here are a few questions i'm stuck on:

4. Humans affect the carbon cycle by
a. burning fossil fuels
b. burning wood
c. driving vehicles
d. all of the above

D?

10. Which of the following is an example of ecological succession?
a. a planted shrub growing on a patio
b. mosses covering the floor of an old building
c. a tomato plant planted in a garden
d. none of the above

i have no idea. this is what my book says about ecological succession:
'ecological succession=a gradual process of change and replacement of the types of species in a community. in nature, the process of ecological succession may take hundreds or thousands of years. Each new community that arises often makes it harder for the previous community to survive. For example, the younger beech trees will have a hard time competing with the older beech trees for sun. However, if a shade-loving species of tree began to grow in the forest, the new species might replace the smaller breech trees.'

51. Artificial selection helps to protect an endangered species by controlling the animal's reproduction and protecting the species from predators.

True or false

true.

that's all. :)

3 answers

Your first answer is correct.

Read the part of your book that you posted here. The answer is obvious.

Check this site for your third answer.

http://en.wikipedia.org/wiki/Artificial_selection
so 4 is D

10 is...C?

and

51 is true
4 is D.

10. is not C. Ecological succession describes natural, not man-made events.

I don't think the last one is true. Does artificial selection protect the species from predation?