Micro-propagation is:
a. propagation of microbes in vitro
b. propagation of plants in vitro
c. propagation of cells in vitro
d. growing plants on a smaller scale
A smaller scale can mean a small flowerpot, so option ‘d’ is incorrect. Microbes and cells are small enough to be easily grown in vitro and hence options a and c are incorrect. Micropropagation is the multiplication of plants in tissue culture. In this technique, part of a plant, cells of plants, tissues, or organs are grown under an in vitro system.
Hence, the answer is option (b) propagation of plants in vitro.