A because a primary source is defined as a first hand account of an event .
Answer:
The correct option is: c. Mercury is closer to the Sun
Explanation:
Mercury is the first and the smallest planet of the Solar system that is present <u>closest to the Sun</u>. The surface temperature of this planet ranges from -173 °C-427 °C or 100-700 K.
Due to the small size and high surface temperature of the planet, the gravity can not retain a significant atmosphere.
Whereas, Moon is the only permanent <u>natural satellite of the planet Earth.</u> It is the second most brightest object in the Earth's sky after Sun.
<u>Since Mercury is much closer to the Sun than the Moon. Therefore, Mercury is much hotter than the Moon.</u>
Answer:
Synthesis :SO3 + H2O —> H2SO4
Single displacement : Pb(NO3)2 + 2NaI —> PbI2 + 2NaNO3
Decomposition : CaCO3 —> CaO + CO2
Combustion : 2ZnS + O2 —> 2ZnO + 2S
Explanation:
Neutrons have the same mass as protons
so the number of neutrons = mass number - atomic number
or for simplicity you can remember it as n=(n+p)-p
