Page 12 - 新思维科学活动用书4 样章

1.3 Skeletons and movement

1.3 Skeletons and movement

Focus

1 Complete the sentences to explain how the pairs shorter

muscles in your arm work. Use each of the words contracts longer
in the box once. relaxes

When I lift a weight, the muscle at the front of my

arm and gets .

The muscle at the back of my arm and gets

. This shows that muscles work in .

2 Label the drawing showing the changes in the arm muscles when
you lower your arm.

arm drops

Practice

3 Fill in the missing words to complete the sentences about how our

muscles work.

Muscles work by on the they are
joined to.

Muscles work in . When one muscle

, the other muscle . The muscle

that contracts gets . The muscle that relaxes gets

.

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