Answer:
Q2->They all form acids when combined with hydrogen. They are all fairly toxic. They readily combine with metals to form salts.
Q3->Because their outermost orbit is complete. In Mendeleev's original periodic table there was no place reserved for noble gas. They were discovered in end of 19th century. So Mendeleev created zero group without disturbing original periodic table.
Explanation:
The answer is <span>2 can be made by the animal's body from other substances.
Both essential and nonessential amino acids have essential roles in the organism. Nonessential amino acids got their name because they are not an essential part of the diet. The main difference between these two groups of amino acid is that essential amino acids cannot be made by the animal's body and must be ingested in the diet unlike the nonessential amino acid which can be made by the animal's body.</span>
The organelle that acts like the brain or the control center in the cell in the nucleus.
Hope this helps!!! :D
Rough ER is studded with ribosomes and the Smooth ER has a smooth surface ..