What can change the water level of a lake?

Correct answer: By rainfall and evaporation

Direct answer: Option A is correct. The water level of a lake depends on its water balance. Water enters through rainfall, streams, rivers and sometimes groundwater. Water leaves through rivers or outlets, seepage and evaporation. Thus rainfall can raise the level, while evaporation can lower it, especially during hot and dry weather. Option A correctly names two real natural processes that can change the level. Option B is wrong because the age of a mountain does not directly control the amount of water in a particular lake. Option C is wrong because the size of the Sun is not the immediate factor controlling a lake’s level; sunlight and temperature can influence evaporation, but the Sun’s size is not a normal local cause. Option D is wrong because the name of a day has no physical effect on lake water. The question tests a simple water-balance idea: inflow tends to increase storage and loss tends to reduce it. Memory cue: rain in, evaporation out; both can change lake level.