Answer:
Endoskeleton
Explanation:
An internal skeleton is called an endoskeleton, which is what vertebrates have. A sponge endoskeleton consists of short, sharp rods called spicules
Spicules are made of silica, calcium carbonate, etc.
Answer:
Phoebus Levene.
Explanation:
Two types of nucleic acids are DNA and RNA. The monomers of mucleic acid contains the pentose sugar, nitrogenous bases and the phosphate group attached with the bases.
Friedrich Miescher was the first scientists who discovered the nucleic acids. He identified the nucleic acids from the bandage that contains the nuclei of white blood cells. The new compounds discovered is known as nucleic acid. But the monomers of the nucleic acids was first explained by Phoebus Levene. Different forms of nucleic acid was also postulated by Phoebus Levene.
Thus, the answer is Phoebus Levene.
Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots usually appear in pairs of opposite magnetic polarity.
