Nitrogen fixed by the bacteria in soil
C. camouflage, camouflage is when an animal is blending in with its surroundings.
The correct answer is a - silicon dioxide.
Diatoms are single celled algae. They have a silica - based cell wall called a frustule, which gives each diatom a particular shape.
Diatoms exist as separate single cells although some may be found in groups or colonies. The ones found in colonies create very pretty forms: leaf shaped, oval , star and even like a period.
Outer shells of diatoms are quite valuable. They are used in industry in the manufacture of toothpaste to give it grit.
The small cell extensions that beat to create an up-ward current are called microvilli.
<h3>What are microvilli?</h3>
Microvilli are small extensions which are found on the surface of the alveoli of the lungs.
The microvilli play an important role in the lungs as the help to remove particles and mucus that may obstruct the lungs as a result of the upward current they create in the lungs from their beating motion.
Therefore, the paralyzed small cell extensions that beat to create an up-ward current are called microvilli.
Learn more about lung microvilli at: brainly.com/question/12993303
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