Which water resource is most likely to dry up for part of the year?

Ponds

Explanation:

Ponds are defined as small and large water bodies that are surrounded by land on all of its sides. In simple words, they are comprised of stagnant water bodies. They receive water mostly from the rainfall and the nearby rivers.

When there occurs changes in the weather and climatic conditions, such as low or absence of rainfall, then rapid evaporation takes place, as a result of which the water is released into the atmosphere, making the pond dry.

So, the ponds are most likely to be dry for some part of a year.

beta decay is the answer