I'd use the library, the encyclopedia and the Internet.
Answer;
The mouth
For ingested foods, the first opportunity for enzymatic digestion occurs in the mouth.
Explanation;
The digestion of food starts in the mouth.
There is both mechanical and enzymatic digestion of food in the mouth. Mechanical digestion involves the mechanical break down of food using teeth to smaller particles thus increasing the surface are for the activity by enzymes.
Enzymatic digestion in the mouth involves enzyme salivary amylase which acts on starch to form maltose.
Answer:
1. Mutation
2. Epigenetics
Explanation:
1. Mutation occurs when there is a change in an organism's DNA sequence as a result of mistakes in DNA replication or as a result of environmental factors like smoking. The mutation in a single organism can be passed on to other generations hence causing a genetic variation in the population, this obeys the Darwin's law that inherited traits (genetic) are passed on to other generations
2. Epigenetics are changes in gene expression that doesn't involve changes in the DNA sequences unlike mutation. This changes can be passed on to other generations and hence cause a variation in the population. This obeys the Lamarckian evolution that acquired traits are passed on to other generations.
A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke.
