Question

why does the water in a swimming pool stay cool on a hot, sunny day? because radiation has no effect on water because of convection because the pool is a good insulator because the suns rays are reflected off of the pools surface

Explanation:

Radiation does affect water, so the first option is incorrect. A pool is not a good insulator. The Sun's rays are not all reflected off the pool's surface. Convection occurs as warmer water rises and cooler water sinks, helping to distribute heat and keep the water relatively cool as heat is transferred to the air above.

Answer:

because of convection