Not 100% sure, but I think its D.
The early atmosphere on Earth was mostly carbon dioxide.
It was also poisonous and extremely hot.
Atmosphere is the gaseous envelope of a planet.
Today's atmospheric functions include sustaining life with oxygen, produced from plants; filtering harmful rays from the sun, helping in protecting the Earth from meteor collisions.
Answer:
A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate. When there's the interaction between two objects they exert a force on each other, these exerted forces are equal in size but opposite in direction.
Peasants had to work the land of a wealthy lord
