Answer:
Creatures of power, creatures of grade, creatures of beauty, creatures of strength. As for their lives, they set everything's pace. For all things must come to live. Under their emerald embrace Either in their life or in their death.
Soft and fragile is my skin, I get my growth in mud. I’m dangerous as much as pretty, for if not careful, I draw blood.
What weaves webs as they grow?
I have four legs but no tail. Usually I am heard only at night.
A hole in a pole, though I fill a hole in white. I'm used more by the day, and less by the night.
I am your mother's brother's only brother in law. Who am I?