More than 90% on the crust is composed of silicate minerals. Most abundant silicates are feldspars<span> (</span>plagioclase<span> (39%) and alkali feldspar (12%)). Other common silicate minerals are </span>quartz<span> (12%) </span>pyroxenes<span> (11%), </span>amphiboles<span> (5%), micas (5%), and clay minerals (5%).</span>
Answer:
I think B is baby teeth and A is permanent teeth
a) Baby teeth doesn't fall on schedule and permanent teeth come in behind them this results is two rows of teeths.
The correct answer is option (C) Gray rabbits would be eliminated by predators.
Camouflage is an adaptation by organisms allowing them to blend with the environment. This helps them in surviving or escaping from their predators. It can be throught coloration or developing a particular pattern or mimicry.
The example given above is a type of camouflage through concealing coloration. Concealing coloration includes having a fixed camouflage and changing the camouflage depending on the environment. Grey rabbits cannot exhibit camouflage as the backgroud is dark rocks and light stones. As a result, these rabbits are clearly visible to the predators and get elimiated by them.
Answer : A metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
Explanation :
The group 16 element are oxygen, sulfur, selenium, tellurium and polonium.
The general electronic configuration of group 16 elements is, 
As we now that there are total 6 electrons in p sub-shell. So, a metal in group 16 can become a chemically stable ion by gaining 2 electrons.
Hence, a metal in group 16 of the periodic table can become a chemically stable ion by gaining 2 electrons.
