The answer is that the pebbles turn into sand
Answer: compound
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water 
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air
★ « <em><u>what is oxidation number of S in H2SO5??</u></em><em><u> </u></em><em><u>»</u></em><em><u> </u></em><em><u>★</u></em>
- <em><u>it's </u></em><em><u> </u></em><em><u>6</u></em><em><u>!</u></em><em><u>!</u></em>
Explanation:
- <em>Oxidation number of S in H2SO5 is 6 .</em>
Benefits of friction.
1. Walking. Friction between the soles of our shoes and the ground enables us to walk. The sole of the shoe is held to the ground through friction. This is what is termed as "grip" of the shoe. The more grip a shoes offers, the better and faster we can walk.
2. Writing. Writing using a pen requires friction. It is impossible to hold a pen in the hand without friction because it would slip out. Also the graphite point of the pencil would not make a mark on the paper without friction.
Drawbacks of friction
1. Drag. An aircraft taking off experiences significant friction between it and the air resulting in drag, so much fuel has to be used to create energy to overcome the wind resistance.
2. Surface hindrance. Friction makes moving something heavy from one part of a room to another very difficult. Sliding a large box across the flour takes a lot of energy due to friction between the box and the floor.
