Pioneer species, I think.
Answer:
A :an atom seeks to fill its outer shell of electrons
Explanation:
Reactions between atoms occur due the desire of an atom to fill their outer shell electrons.
The driving force for many interatomic bonding is the tendency to have completely filled outer energy levels like those of the noble gases.
- The various interatomic interaction which leads to chemical reaction is in a bid for the atoms to be isoelectronic in the outer energy level with the noble gases.
- This is achieved by gaining, losing or sharing of electrons.
The tilt of the earth's axis, which essentially "turns" certain parts of earth so that some parts receive more direct sunlight
Acid rain<span> is caused by a </span>chemical<span> reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other </span>chemicals<span> to form more </span>acidic<span> pollutants, known as </span>acid rain<span>.</span>