Some quick Biology questions please (multiple choice)!?

[browney]

Having trouble with a few questions.. Thank you

1.Complementary RNA bases are paired with DNA bases when..
A. mRNA attaches to a ribosome.
B. codons and anticodons pair up
C. RNA polymerase passes over each DNA nucleotide.
D. translation occurs in the nucleus of the cell.

2. Which is not found in DNA?
a. adenine
b. cytosine
c. uracil
d. none of the above

3. A _______ is any agent that can cause change in DNA.

Oh and if anyone could give me a link to a good illustration of translation, I couldn't find a good one! that would be fantastic.