The answer is "Decomposers directly convert ammonium into nitrogen gas".
Living organisms such as plants and animals contains nitrogen in the form of the amino acids and proteins. When they die, the nitrogen in the form of ammonium is decomposed by microorganisms. It is then converted into nitrites and then to nitrates by nitrifying bacteria. The denitrifying bacteria then converts nitrates into nitrogen.
Purines: adenine and guanine
Inner core was found to be solid after observing the motion of P waves.
Explanation:
Seismologist Inge Lehmann, studied the seismic waves of an earthquake and discovered about inner core in the mantle layer of Earth. She States that there is a boundary of discontinuity between the outer and inner core of Earth.
She studied the travel of secondary and primary waves during an earthquake and how it flows at different shells of Earth's layer which helped her in finding about the inner core of mantle. She observed that the inner core is a solid layer inside the molten layer of outer core
