The basic reason why unripe fruits have defensive chemicals is that they need to protect the seeds that are not ready to germinate. On the other hand, the seeds of the ripe fruits are ready to germinate and so they need to get spread with the help of animals and birds and so there are no defensive chemicals. These seeds spread to different places and the soils help them to germinate under suitable conditions.
DNA replication occurs within the nucleus of a cell
Chlorella is a genus of about thirteen species of single-celled green algae belonging to the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll-a and -b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce.
Your Answer would be 3. Also known as Lithium.