Usually scientists looking for life on other planets try to determine first if the planet had or has evidence of water. Develop a rationale for this based on cellular chemistry

water is essential for life as we know

Explanation:

Water (H2O) is essential for life (i.e. carbon-based life) because this molecule has unique chemical properties. First, water is a universal solvent that helps cells to transport and use essential molecules (e.g., oxygen and nutrients). Second, water molecules help cells to maintain their shape/structure by generating pressure within the cells. Third, the polarity of water helps the formation of phospholipidic membranes because phospholipids have polar heads that interact with water and nonpolar tails that interact with each other. Fourth, water has a high heat capacity, thereby helping to regulate the temperature in the (intracellular) environment. Finally, water molecules also have unique adhesion and cohesion properties that enable the movement of substances against gravity (adhesion) and create a surface tension (cohesion) that helps to the formation of bubbles with water.

a, i am pretty sure.