Provide at least three reasons why friction is needed.

Sample Response: Friction allows people and objects to move. It provides traction for an object to start moving or change direction. It can also give people a better grip on objects. Finally, friction keeps objects in place when they are set down.

-Friction makes movement possible.

-Friction provides traction

-Friction makes it easier to hold on to objects

-Friction keeps objects in place.

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.