Which statement correctly describes the difference between meiosis i and
meiosis ii?
a.) meiosis i brings together sister chromatids, and meiosis ii separates them.
b.) meiosis i separates tetrads, and meiosis ii separates sister chromatids.
c.) meiosis i separates sister chromatids, and meiosis ii separates tetrads.

I'd go with this one: b.) Meiosis I separates tetrads, and meiosis II separates sister chromatids. As it is correctly describes the difference between meiosis I and meiosis II.

Where are the following choices

Essential for a scientist to do for credibility

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.