Answer:
The formation of magnesium chloride, MgCl2, is another example of ionic bonding. When magnesium reacts with chlorine, a magnesium atom loses two electrons and becomes a positively charged ion, Mg2+. At the same time, two chlorine atoms gain one electron each and become negatively charged chloride ions, Cl−.
Grafting in citrus plants and mango, layering in jasmine
<u>Answer</u>: Option 3 Coevolution
<u>Explanation</u>:
<em>Coevolution</em> is a process in which two individuals reciprocally affect each other's evolution. In this process the interacting species exert selective pressures on each other thus, affecting their evolution. Due to this reciprocal adaption they become so close that the evolution of one species is affected by the other.
A male and female, sperm and egg.