The volume of a given mass of an ideal gas at constant pressure is 1. directly proportional to the kelvin temperature
2. directly proportional to the celsius temperature
3. inversely proportional to the kevin temperature
4. inversely proportional to celsius temperature

inversely proportional to the kelvin temperature

Explanation:

PV=nRT

1. directly proportional to the kelvin temperature

Explanation:

Refer to the Ideal Gas Law, PV = nRT. As the temperature, which is always in Kelvin when part of the Gas Law, increases, the pressure would increase as well, meaning that they're directly proportional.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.