Further microscopic analysis of negatively stained specimens reveals a colorless ring around each of the spherical cells against a dark background. This clearing indicates that the pathogen possesses which structure(s):. a. endospores. b. a capsule. c. nucleoid. d. pili.

b. a capsule

Explanation:

The capsule is mainly made up of polysaccharides and surrounds many bacteria. Capsule staining includes mixing of the bacterial cells with dye and spread out in a thin film on a slide. After air-drying, the cells appear as light-colored structures present in a relatively dark blue-black background. This occurs since the dye particles cannot penetrate either the cell or its capsule. Therefore, the given slide with a colorless ring around the cells in a dark background represents the presence of a capsule around the observed cells.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.