Most likely, no. BioWare has said that Mass Effect is a triology, which means there will only be three games.
Depends on what you like better. Both Role-Playing Games. Skyrim is a hardcore rpg game and mass effect is more focused on story. Personally i like mass effect better.
If there is more mass, there will be more gravitational attraction.
This is up to you. But, my opinion is that you should definitely play ME1 first. You get a better feel on the Mass Effect Universe, and you will be more attached to the game, and will enjoy ME2 a lot more. Mass Effect 1 is a great game, as is Mass Effect 2, but if you have the time and the money, play ME1 first.
The bigger the object is the more mass it has.
population can effect the environment because more people are going to litter so its going to kill more animals
While not absolutely necessary, Mass Effect has a few story perks from decisions you made in Mass Effect. If you want the full Mass Effect story you should definitely pick it up as nothing does more justice to the game than playing through it.
absolutely, it will mostly effect how quickly it will accelerate relative to its mass, and how quicky it will fall (descend hills) and how slowly it will stop, more mass = slower deceleration. Also a bigger mass will maintain the conservation of momentum more easily.
The mass affects the efficiency of an object. It adds more weight, which causes more friction. More friction=less efficiency
By virtue of having mass. Anything with mass will have a gravitational effect. The more mass the greater the gravitational force.
it might but it puts more matter were it is happening
Yes, the larger the mass the more the object is going to weigh.
No. The mass of a planet affects the number of moons it has. More massive planets tend to have more moons.