The answer is D. Identity of an element is determined by the number of protons, also called the Atomic Number. On the periodic table the atomic number is found above the element name. If you take away or add a proton, the element is not the same element anymore
Nitrogen-fixing bacteria change nitrogen into a form of soluble nitrates that plants can use ...the air is 80% nitrogen but it is in N2 form which plants cannot use
Answer:
a green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis. Its molecule contains a magnesium atom held in a porphyrin ring.
