Answer:
The concept of lewis acids and bases can explain the acidic nature of CO2. A lewis acid is a compound which can accept an electron pair whereas a lewis base is a compound which can donate an electron pair. CO2 acts as a lewis acid.
The average atomic mass of the imaginary element : 47.255 amu
<h3>Further explanation </h3>
The elements in nature have several types of isotopes
Isotopes are elements that have the same Atomic Number (Proton)
Atomic mass is the average atomic mass of all its isotopes
Mass atom X = mass isotope 1 . % + mass isotope 2.% ..
isotope E-47 47.011 amu, 87.34%
isotope E-48 48.008 amu, 6.895
isotope E-49 50.009 amu, 5.77%
The average atomic mass :

Well there are 1,000 milligrams in 1 gram so 9.815 grams of sugar is equivalent to 9,815 milligrams of sugar. So a bar of milk chocolate contains 9,815 milligrams of sugar.
Solar- the sun is not always shining, for example at night you can't get any energy from the sun
Wind-it's not always windy
Water- there can be drought
Really the main issue of all three of these is that they are not always available