What is a biofilm?
a. A group of bacteria that accumulate in layers and secrete a protective extracellular material
b. A layer of sugars that persist even after bacteria have been killed by antibiotics
b. Free-floating bacteria that move through the blood to other sites
c. A bacterial cell that secretes an extensive network of fibers around its cell wall

A group of bacteria that accumulate in layers and secrete a protective extracellular material. (Option A)

Explanation:

Biofilm is defined as one or more types of microorganisms collectively grow in different places. Organisms that form the biofilm include protests, fungi, and bacteria.

Dental plaque is an example of a biofilm. It is a known buildup of slimy bacteria that forms on the teeth surface. Biofilm can grow on different surfaces such as animal tissues, plant tissues, minerals, metal, etc.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.

can you make it bigger i can't see it