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.
Polar bears are listed in red as they are belong to Endangered Species. These species are gonna extincting due to gradual changes by environmental factors.
Answer:
I believe that the answer is c.
Explanation:
car·ti·lage
/ˈkärdlij/
noun
firm, whitish, flexible connective tissue found in various forms in the larynx and respiratory tract, in structures such as the external ear, and in the articulating surfaces of joints. It is more widespread in the infant skeleton, being replaced by bone during growth.
During Light reactions of Photosynthesis, the chlorophyll will be activated by light. This light activated chlorophyll will split the water molecule. This is called Photolysis. Water molecule is split to release H+ ions and also oxygen.
