The answer is A
Answers B, C, and D are mentioned on the website, but answer A isn't mentioned
Answer:
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.
Answer:
The easiest way to think of this is to imagine a bird with a wide jaw and a hooked beak that solely eats caterpillars. This would not be a problem for the bird if they are in the open air, but if they go into a crevice, or they go into a hole of a tree, they will be impossible to get.
I hope this helps!
