Answer to Question 1
Airless bodies develop where solar heating is strong and/or gravities are weak. Simply stated, small warm bodies have a better chance of losing their atmospheres because gas molecules are more energetic and need less speed to escape their weak gravities.
Answer to Question 2
The Moon originated from the impact of a large planetary body colliding with early Earth and tearing out a large chunk of molten Earth material that cooled within orbiting range and was kept within orbiting range by gravity.
Estimated terrestrial net primary productivity across Canada.
Dwarf Planets
Accretion of the Inner Planets
Location of the Planets Relative to the Sun
Inverse Relation Between IQ and Disease. Could this explain the Flynn effect?
Terrestrial Planets "الكواكب الأرضية"