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

need help with the same things

I need help with 2

For the first question, the correct answer is:

His arm muscles work in pairs so that one contracts while the other relaxes to hold his arm in position.

When the rock climber grasps onto a ledge, the muscles in his arm work together in a coordinated manner. The major muscles involved in gripping and holding onto the ledge are the flexor muscles and the extensor muscles. The flexor muscles bend the fingers and wrist, while the extensor muscles straighten them. These muscles work in pairs, with one muscle contracting while the other muscle relaxes. This allows the climber to maintain a firm grip on the ledge.

For the second question, the correct answer is:

Both sets of muscles are involuntary and smooth.

The muscles located in the walls of the small intestine and the arteries are both types of smooth muscles. Smooth muscles are involuntary muscles, meaning that they are not under conscious control. They contract and relax automatically in response to certain stimuli. In the case of the small intestine, the smooth muscles contract rhythmically to help move digested material along. In the case of the arteries, the smooth muscles contract and relax to help push blood along.

For the third question, the correct answer is:

solid; lightweight

Despite their solid structure, human bones are surprisingly lightweight. Human bones are composed of a combination of hard and compact outer layers and spongy inner tissue. While they are solid and provide support and protection for our bodies, bones are also designed to be lightweight. This is important for our mobility and overall physical functioning.