Final answer:
Some insects can walk on water because of the high surface tension of water and the adhesive forces between the water and their hydrophobic legs. Surface tension is due to the cohesion among water molecules. While buoyancy plays a role, surface tension is the primary reason, making 'd) All of the above' the correct answer.
Step-by-step explanation:
Insects such as water skaters are able to walk on water primarily because of the surface tension of water. Cohesion among the water molecules at the surface creates this tension, making it difficult for the surface to be penetrated. The high surface tension, combined with the hydrophobic legs of some insects that repel water, allows them to stand and move across the water without sinking, as long as their body weight is sufficiently low to not break the surface tension.
Their weight is distributed over their long, slender legs, which increases the surface area in contact with the water. This, along with the surface tension, which is a result of the strong cohesive forces among the water molecules due to hydrogen bonding, provides enough support for them to remain on the surface. The buoyancy of an insect's body can also contribute to this effect, but to a lesser degree in comparison to surface tension.
Therefore, the right answer to why some insects can walk on water is: a) Due to the high surface tension of water, and b) Because of the adhesive forces between their legs and water molecules, which means both a) and b) are correct. However, the primary reason is c) the buoyancy of their bodies. So, 'd) All of the above' is the most comprehensive answer to the question, inclusive of all contributing factors.