An insertion mutation occured.
After the mutation, a letter was inserted, and the others remained intact. The number of letters increased by 1.
The folds in the stomach lining are called rugae. On these rugae, you will find a thin line of mucous which helps protect the stomach lining. The innermost layer is called Simple Columnar Epithelium.
i believe the answer u might be looking for is number 3. plants breathe carbon dioxide, so an increase in plant life could help aid world hunger.
