Answer:
Answer is 4
Explanation:
Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms. ... If the electronegativity of two atoms is basically the same, a nonpolar covalent bond will form, and if the electronegativity is slightly different, a polar covalent bond will form.
Answer: An alpha-particle is identical to the nucleus of a normal (atomic mass four) helium atom i.e. a doubly ionised helium atom. Alpha particles (also termed alpha radiation or alpha rays) was the first nuclear radiation to be discovered, beta particles and gamma rays were identified soon after.
The correct answer is greenhouse gases. It is the most abundant gases among the choices in the atmosphere. These gases are water vapor, methane, nitrous oxide, ozone and carbon dioxide. Without these gases, the temperature of Earth will be about -18 degrees Celsius.