the gravitational force
Gas
A protostar forms when gravity pulls the dust and gases in a nebula together.
It varies from same as in a solid (glass, mercury), to that of a gas (and check out the "triple point") You should study - surface tension.
it is a gas but when it condenses it becomes a liquid
The interstellar medium is all the matter that exists between the stars in a galaxy. It mainly consists of gas (99%), with about 75% of this gas being in the form of molecular or atomic hydrogen, and about 25% in the form of helium. The other 1% is in the form of dust. The density of the interstellar medium is also very small: about 1 atom per cubic centimetre.There are two main types of interstellar mediums:Cold clouds of neutral atomic or molecular hydrogen, which are the raw materials wherein stars can be formed if it becomes gravitationally unstable and collapses.Hot ionized hydrogen near hot young stars.
An interstellar cloud made of gas, dust, and plasma in a galaxy.
An interstellar cloud.
A nebula IS a cloud of dust and gas loosely held together by gravity.
A nebula is what it is. :)
solar nebula
These are generically referred to as, not surprisingly; 'interstellar clouds'
As an interstellar gas cloud shrinks in size, it's gravitational potential energy gradually transforms into other forms of energy.
With all due respect, an interstellar cloud is, by its definition, gas, plasma and/or dust (molecular particulates) in greater quantities than normally found in interstellar space. So, perhaps the answer is No, because there are other elements present.
a nebula
The solar system was previously a cloud of interstellar gas.
The solar system formed from the gravitational collapse of a cloud of interstellar gas.
No, The nebula is an interstellar cloud of dust, hydrogen gas, helium gas and plasma. Look on Wikipedia.