9) There are four forces acting on the box: A spring pulls with a force of 40 N. The force of gravity acts downward; and the force of the table is pushing up on the box. What MUST be true of the frictional force if the box moves across the table?

A) It is equal to the effort force.

B) It is less than the effort force.

C) It is more than the effort force.

D) It is equal to the force of gravity.

the answers are a and c

c should be the answer

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.