Answer:
A carbon atom can form up to four covalent bonds as one carbon atom has four valence electrons (in outermost shell). It is a fact that the number of valence electrons in a atom determines the number of covalent bonds it will form. Thus, each electron in carbon atom is used to form four covalent bonds with various four atoms.
Explanation:
A bond between a carbon and hydrogen atom is a non-polar covalent bond. The non-polar covalent bond are the bonds between two atoms which share equal number of electron(s) with each other. Example: as in case of methane, where one carbon atom shares its 4 outer valence electrons with four hydrogens by sharing equal number of electron.
In contrast, polar covalant bond are the bonds between two atoms which share unequal number of electron(s) with each other. Thus these bonds are partially ionic.
Fresh water is any body of water with a low salt concentration. Organisms in fresh water various challenges which includes; Osmotic concentration such that fresh water is permanently dilute and most cells cannot function at this concentration of ions. Varying temperatures, variation in oxygen levels and reproduction and life cycle due to permanence of habitat and physiological difficulty of regulating osmotic concentration in larvae and juveniles.
Vary in the number of neutrons but Sama in the number if protons are called isotopes