You find that it takes 4 n force to pull a 2-kg block on your desk horizontally with constant velocity. the friction force between the block and desk is?

it doesn't. it was imagined up in the middle ages.

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.

i think the answer is tomato juice? not entirely sure though