23. Human locomotion is made possible by the A) involuntary contraction of tendons
B) involuntary contraction of ligaments
C) voluntary contraction of smooth muscles
D) voluntary contraction of skeletal muscles

You see a white marker with an orange circle and black lettering. what does this marker tell you

What is the problem in this article? what solution does the article propose?

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of