Question

Which of the following may have happened if the inner planets had greater masses during the formation of the solar system?

A. The inner planets may have been even smaller and rockier.
B. The inner planets may have been larger and more gaseous.
C. The inner planets may each have had ice on their surface.
D. There may have been only three inner planets.

Answer 1

Gravity is dependent on mass. The greater the mass, the stronger it's pull is. Now assuming that the sun is till the center of the universe, if the planets' pull is stronger, they will be closer to the sun. However, just because the mass is greater does not mean it's smaller.

Given that, what do you think?

Answer 2

Let me correct that last sentence. Mass and size are not related is what I should say.

Answer 3

so then it would be d, right?

Answer 4

"...the planets' pull is stronger..."
so Mercury will be closer to the sun, but it will also pull Venus and the earth closer to it.
Venus will pull Mercury closer to itself, but it will also pull Earth and Mars closer to itself
Earth will pull Venus closer to itself.....etc etc

Answer 5

"...if the planets' pull is stronger, they will be closer to the sun..."
"... However, just because the mass is greater does not mean it's smaller..."
Both these concepts ^^ follow the same kinematics. And it is hard to predict their solution only on the basis of mass.
e.g. The trajectory of a projectile/satellite is independent of its mass.

"...so Mercury will be closer to the sun, but it will also pull Venus...Earth will pull Venus closer to itself..."
Three body system is too complex for this approach.

I am not really sure if this question has a unique answer; but given the choices, I'll go with -
"B. The inner planets may have been larger and more gaseous. "
e.g. Moon has lesser mass than Earth and hence lacks atmosphere.