Final answer:
Clay/mud is the sediment type typically found in lake bottoms because these fine particles settle in the low energy environment of the lake.
Step-by-step explanation:
The sediment typically found at the bottoms of lakes is clay/mud. This is due to the generally low energy environment within lakes, where fine particles like clay and mud settle out of the water and accumulate over time. This accumulation can also include organic material and the remains of tiny organisms that contribute to the muddy substrate. In contrast, higher energy environments such as rivers can carry and deposit larger sediment like gravel, but these are not usually found in the calm conditions present at the bottom of lakes. For example, Lake Winnipesaukee in New Hampshire showcases such lake settings where sand, silt, or clay can be found due to its low energy environment.