Answer: with a higher abundance of hydrogen compounds and larger size
Explanation:
Suppose the solar nebula had cooled much more before the solar wind cleared away the remaining gas. In that case, the terrestrial planets likely would have ended up with a higher abundance of hydrogen compounds and larger size. Though during the formation of the planets there were abundant fractions of hydrogen and helium but due to the high temperature around the terrestrial planets the hydrogen gases were not able to condense on the terrestrial planets resulting in lower abundance of hydrogen compounds in the terrestrial planets when compared to other planets where the temperature allows hydrogen gas to condense before the solar wind cleared the remaining gas. For more information you can read about the formation of the solar system and nebula hypothesis
When the spacecraft is at halfway point, the distance from the Earth as well as Mars are same. We have to account the masses of the planets. The gravitational force that is exerted by the Earth is greater because of its combined mass with the space probe.
The mass of Earth is greater than the mass of Mars. Therefore, the force of Earth is more than Mars.
Answer: yes a quantity have different dimensions in different system of units . No,because in different system of units doesn't change the quantity but it only changes the numerical.