4. what type of substance would be best for use in a heating system?
a liquid with a high specific heat
a liquid with a low specific heat
a gas with a low specific heat
an explanation of why the answer is right.

The best answer is a liquid with low specific heat. For every heating medium used in a heating system, it is important to have a substance with a low specific heat, so that it will easily reach the desired heating temperature. This saves on cost because you will need less energy to increase the temperature of your medium. A liquid is also better than a gas because liquids are able to give off more energy (latent and sensible heat) than gases.

Answer : option a) 84explanation :

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

Any vitamins or supplements can be obtained without prescription and are widely used as alternative from western medications. most supplements are not valued by the fda or any other drug and food agencies.