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.
Answer:
Leaves, grasshopper, snake, fox
Hi,
The rda is designed to be averaged over several days.
- true
(average across a number of days, because body is good at storing based on solid, reliable evidence and observations).
Protons are located C) in the nucleus with neutrons. Hope this helps!
For the answer to the question above, I believe the answer is <span>A. vaccine helps the body develop memory cells that make immunity last, whereas injection of antibodies only produces a temporary immunity.
I hope my answer helped you. Have a nice day!
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