Answer:
A. Rock pieces
Explanation:
Abrasion is the breaking down and wearing away of rock material by the mechanical action of other rocks. Three agents of physical weathering that can cause abrasion are moving water, wind and gravity. None of those are agents of abrasion. But Rock pieces are a result of abrasion.
Electron pairs , because the atoms become stable by gaining the electron pairs
Genetic variation enables bacteria to adapt to changes in their environment. Since, bacteria reproduce asexually (binary fission), they can share genes (genetic transfer) via other mechanisms such as conjugation (exchange of genetic material through direct contact between two bacteria), transformation, and transduction(exchange of genetic material via bacteriophages).
Transformation is a process by which bacteria takes in DNA from its environment through the cell membrane.