<u>Answer: </u>
For 1: The correct option is b.
For 2: The correct option is a.
<u>Explanation: </u>
Earth is the third planet in our solar system. It's placement in the solar system is such that, it is the only planet on which life survival is possible.
Earth lies in the Goldilock zone that defined as the zone in which there is an accurate temperature and atmospheric conditions which supports the life.
So, this placement most affects earth's unique temperature and atmospheric conditions. Hence, the correct answer is Option b for 1 and Option a for 2.