It has grown exponentially. Due to the offspring of several generations having longer lifespans, it's become a lot easier for the population to grow.
The right answer is B active immunity.
For information, there is no complete immunity and incomplete immunity in immunology.
Active immunity is a form of immunity that protects the body through the production of antibodies when exposed to a first infection or vaccination.
This type of immunity is persistent. Example of measles: previously safe measles viruses are applied during vaccination.
A covalent bond is also called a molecular bond. it’s the chemical bond that involved the sharing of electron pairs between the atoms.