Answer: A) Water B) Habitat
Explanation: One of the first things scientist consider when discovering new planets is a source of water. WIthout water there is no possibility at all for life. Every living thing from cyanobacteria to the biggest living thing on earth all need water to survive. Additionally, without a liveable habitat suited to that of the organism living there, it is certain that life would not be sustainable. However, water is the most important by far.