Explanation:

Statement 1: Yeasts are unicellular organisms which evolved from multi-cellular ancestors, with some species having the ability to develop multi-cellular characteristics.
Yeasts, with their single-celled growth habit, can be contrasted with molds, which grow hyphae.
S2 and S3: By fermentation, the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols – for thousands of years the carbon dioxide has been used in baking and the alcohol in alcoholic beverages.
During anaerobic respiration, they yield alcohol.
It is also a centrally important model organism in modern cell biology research, and is one of the most thoroughly researched eukaryotic microorganisms.

Researchers have used it to gather information about the biology of the eukaryotic cell and ultimately human biology
Learning: Some yeasts can find potential application in the field of bioremediation. One such yeast, Yarrowia lipolytica, is known to degrade palm oil mill effluent, TNT (an explosive material), and other hydrocarbons, such as alkanes, fatty acids.