Answer:
Epithelial cells
Explanation:
Epithelial cells are cells that secret mucus to prevent friction between organs. Like between the Heart and Lung.
Answer:
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. Mutations can occur during DNA replication if errors are made and not corrected in time. This type of mutation occurs when the addition or loss of DNA bases changes a gene's reading frame. A reading frame consists of groups of 3 bases that each code for one amino acid.
Explanation:
Yes an atom is a substance.
What is it with all these hiv questions but idk sorry i need points
