The correct answers are: 1, 3 and 4.
Jaden would be an effective participant in the group discussion because he has carried out thorough research on the subject, and therefore will be able to answer questions correctly.
He has also reviewed available material, such as teacher's feedback reports from previous science projects.
And at the same time he has researched projects from past science fairs, so he can support his oppinions on their success or failure.
The cost of goods and services will increase
I'm assuming the underlined pronoun is <em>her</em>, because that is the only pronoun. Then, the correct answer is D) Tracey.
Antecedent means that the pronoun refers to the subject before it.