What is algae. give short explanation

Algae is a type of plant can live with little oxygen(which is the reason they can grow under water

Algae are diverse group of aquatic organisms that have the ability to conduct photosynthesis...
"algae" covers many different organisms capable of producing oxygen through photosynthesis 

The proton has a positive charge while the neutron has no charge they both make up the nucleus of the atom while the elections have a negative charge and surround the nucleus of the atom. the protons and electrons are used to calculate the atom's mass whereas the neutrons don't affect the mass