A rock climber grasps onto a ledge in the rock wall. How do the bones and muscles in his arm interact to allow him to hold on?

photo of a man climbing a rock wall
All of the muscles in his arm contract to hold his arm in position.
His arm muscles work in pairs so that one contracts while the other relaxes to hold his arm in position.
His arm muscles work independently of each other to hold his arm in position.
All of his arm muscles relax to hold his arm in position.

Muscles located in the walls of the small intestine help push digested material along. Muscles located in the walls of arteries help push blood along. Based on this information and your understanding of muscle types, which of the following statements is correct? (1 point)

Both sets of muscles are involuntary and smooth.
Both sets of muscles are voluntary and smooth.
Both sets of muscles are smooth, although one set is voluntary, and the other set is involuntary.
Both sets of muscles are voluntary, although one set is striated, and the other set is smooth.

Which of the following sets of words best fills in the blanks in the following sentence?

Despite their ______ structure, human bones are surprisingly _________.
solid; lightweight
compact; flexible
spongy; fragile

2 answers

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