There are two types of thirst and intracellular thirst and extracellular thirst. Extracellular thirst (dehydration) can be ruled out as it only requires water and salt to regenerate blood, at it's correct osmality. On the other hand, intracellular thirst (dehydration) can be corrected by drinking water alone. Therefore, the answer to this problem is intracellular thirst due to thirst for plain water.
Explanation: You can see that the green colored frogs were once lower than the blue and as time started progressing the green started getting a higher population over the blue, as the blue decreased.
I believe the answer is Yy. Although Y represents the dominant trait for yellow, it being paired with the recessive trait, y, has the chance of a plant with green seeds to be produced in the next generation.
