In which scenario is an animal doing work? check all that apply.

a cat lifts up her kitten by its neck.
a dog rubs his back against a large tree.
a bird carries a worm to its nest.
a goat butts its head against the barn wall.
a horse pulls a wagon along a road.

A cat lifts up her kitten by its neck.

A bird carries a worm to its nest.

A horse pulls a wagon along a road.

Explanation:

Work is defined as the product between the force applied to an object and the distance the object has been moved:

therefore, work is non-zero only if the object has been moved by a distance different from zero. This is exactly what happens in the three following scenarios:

A cat lifts up her kitten by its neck.

A bird carries a worm to its nest.

A horse pulls a wagon along a road.

In all these cases, an object (the kitten, the nest and the wagon) are moved through a certain distance, so work is done. On the contrary, in the other two examples:

A dog rubs his back against a large tree

A goat butts its head against the barn wall.

No object is moved, so d=0 in the formula and no work is done.

colorectal cancer may also develop from areas of abnormal cells in the lining of the colon or rectum. this area of abnormal cells is called dysplasia and is more commonly seen in people with certain inflammatory diseases of the bowel such as crohn's disease or ulcerative colitis.

the ima (higher than 1m) will be greater than the ima with the height of 1m.