Which of these example of chemical change? breaking glass melting ice on the windshield burning gasoline denting a bumper

Your answer is burning gasoline. if you think about it, none of the rest of the answers really involve chemicals. ice isnt known as a chemical, and so isnt glass. and if your dent a bumper, it doesnt make sense to add it as a chemical change. so your answer is burning gasoline. hope this helps.

Ithink the dna sequences may vary but the amino acid sequences are identical. 

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.