The answer is nuclear energy
D. All of the above are indicators of chemical change
<u>Answer:</u> The element represented by M is Strontium.
<u>Explanation:</u>
Let us consider the molar mass of metal be 'x'.
The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol
It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

The metal atom having molar mass as 87.62/mol is Strontium.
Hence, the element represented by M is Strontium.
The definition of a gem is "a precious stone, cut and polished for jewelry. They are all minerals. Some highly desirable gemstones may not be suitable for jewelry, yet be very collectible, like sphene. Others, like those in the corundum family, are prized for color and hardness, like emeralds and diamonds. Further, some common minerals, when polished, make beautiful pieces. With all that said, i woukd go with rarer.
Answer:
Coal
Explanation:
Coal is composed of the remains of dead animals and plants, being pressed down over the course of thousands of years.
(Also can I please have Brainliest? I need it to level up)