system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do fleas jump so high for their body size?
gpt
As something gets larger, it's weight goes up proportional to it's volume, and it's strength goes up proportional to the cross sectional area of it's muscles. Volume scales as the third power, area scales as the second power. 

So, very large things are much weaker for their size as compared with very small things. 

Of course, this doesn't explain why, for example, ants aren't great jumpers, while fleas are. 

It turns out fleas have a cool spring like mechanism that they can bend and store energy. When it releases, it propells them higher than their muscles alone can.