If a lake's water level is continuously falling which combined cause should be checked first?

Correct answer: Excessive water withdrawal and low recharge

Direct answer: A, excessive water withdrawal and low recharge. A lake’s level depends on water balance: water entering the lake must be compared with water leaving it. Step by step: excessive withdrawal removes more water for homes, farming or industry; low recharge means less rainwater or groundwater replaces it; total loss then becomes greater than total input; consequently the lake level falls. Option A is correct because it gives two directly connected causes. Option B, solar and lunar eclipses, are temporary astronomical events and do not normally control a lake’s continuing water balance. Option C, volcanic smoke and a meteor, are not the usual combined explanation for gradual level decline. Option D, sea ice and mountain colour, have no direct water-balance connection in this context. Other causes may also be investigated, such as drought or evaporation, but A is the best listed combined cause. Memory cue: less input plus more output means falling water level.