Answer
See explanation.
Work Step by Step
a. Cutting of food is a physical change, as it does not change the chemical composition of the food, it just changes the physical state, cutting the food into smaller pieces.
b. Interaction of food with saliva and digestive enzymes is a chemical change, as enzymes and chemical reactions are involved in breaking down the food molecules into smaller molecules, this process is a chemical change.
c. Proteins being broken down into amino acids is a chemical change, as proteins are made up of chains of amino acids, and breaking these chains down into individual amino acids is a chemical change.
d. Complex sugars being broken down into simple sugars is a chemical change, as complex sugars are made up of chains of simple sugars, and breaking these chains down into individual simple sugars is a chemical change.
e. Making maple syrup by heating maple sap to remove water through evaporation is a physical change, as it does not change the chemical composition of the sap, it just changes the physical state, removing the water and increasing the sugar concentration.
f. DNA unwinding is a physical change, as it does not change the chemical composition of the DNA, it just changes the physical state, the double-stranded DNA unwinds to become single-stranded, which is important for the replication of DNA.
