Explanation:
Tarbuck, Earth's crust is made up of several elements: oxygen, 46.6 percent by weight; silicon, 27.7 percent; aluminum, 8.1 percent; iron, 5 percent; calcium, 3.6 percent; sodium, 2.8 percent, potassium, 2.6 percent, and magnesium, 2.1 percent
About 29% of Earth's surface is land consisting of continents and islands. The remaining 71% is covered with water, mostly by oceans but also lakes, rivers and other fresh water, which all together constitute the hydrosphere.
...
Earth.
Almost 99% of the minerals making up the Earth's crust are made up of just eight elements. Most of these elements are found combined with other elements as compounds.
This rock can be classified as:
an igneous rock.
Igneous rocks are made up of
randomly arranged interlocking crystals and the important minerals that can be
found in igneous rocks are feldspars, quartz, olivines, pyroxenes, amphiboles,
and mafic minerals. All of these minerals are important in the formation of
almost all igneous rocks, and they are basic to their classification.
It is A. Those are all decomposers, the other answers like C are all animals. Decomposers are are biotic organisms that break down basically dead plants or animals.
The measure of side b as 64 ft is incorrect. The accurate measure would be 8 ft.
According to the Pythagorean theorem, the square of the hypotenuse of a right-angle triangle is the sum of squares of the opposite and the adjacent sides. Mathematically:

In this case, the hypotenuse = 10 ft, the opposite = 6 ft and the adjacent = b
Hence,
b^2 = 10^2 - 6^2
= 100 - 36
= 64
b = √64
= 8 ft
Thus, the side b is 8 ft and not 64 ft.
More on the Pythagorean theorem can be found here: brainly.com/question/16426393