An example of a chemical change is a) burning wood. b) breaking a glass. c) folding paper into a frog. d) molding clay into a snake.

A chemical change changes the chemical identity of a substance, whereas a physical change does not.

Combustion takes a hydrocarbon and produces water and carbon dioxide. Breaking glass takes one piece of glass and makes it smaller. Folding paper changes its shape, as does molding clay.

In general, if there is evolution of gas, formation of a precipitate, or a color change, a reaction has usually occurred. The answer is A.

Burning wood. At the beginning, the wood is left untouched. When lit it burns, causing it to have a different effect.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.