C) matter is changed into various forms but the total quantity remains unchanged.
"Net force" simply means the sum of all forces. The "unless acted upon by a net force" version is more correct. For example, as you stand or sit still, the earth pushes you up with a force equal and opposite to the force with which gravity pulls you down. The net force, or total force, is zero, so you do not move.
Yeasts is a fungus that is unicellular
The human eye is grief in damage of in-depth perception, color recognition, and peripheral vision. Judging speed and distance based on visual evidence is also more difficult in the dark. In addition, the darkness of night, and even the dimness of dusk and dawn.
