The human form, physical and intellect, seems well suited for manipulating the environment.

As successful as it is on our planet, maybe the humanoid form is the dominant life form on other worlds.

Could you think of a more efficient life form able to change or adapt to its environment in any way using intellect
and imagination?

Anything we lack physically, we make up for in technology. Humans fly at thousands of MPH at the edge of space, dive miles beneath the oceans, live anywhere on the planet and explore beyond the confines of gravity.

We also have created the computer to augment our thought processes and to do the work of tedious million of calculations that allow us to model our environment further.

What I wonder about is the scale of life forms currently on earth. Most land animals are less than six feet in height and vegetation is limit to a few hundred feet.

What are the factors that limit the size of life forms?