I think the word you're looking for is "hypothesis".
For example, a hypothesis could be "dogs drink more often when owners are present".
And then this can be proven (or dis-proven) by an observation (or in this case rather: measurement).
Answer:
their wasn't many human rights violations gender roles began to change due to different invention from tampons to birth control witch made it possible for women to take on different roles. This applies to western countries next we have the different ideals and cultures for example middle eastern countries were women are treated as property and are beat and killed with no punishment to the aggressor. The 2 things i would focus on is religion and and culture witch leads to the ideologies in these places
Explanation:
In most urban areas, it is very common that there is a lot of pollution as a result of all the cars and pollutant producing things like vehicles. Thus making it quite a problem as it can have many health implications (if on a large scaled (see cities like China where people have had to wear masks to prevent any toxication)). Pollution also contributes to global warming which is an ongoing issue that affects the entire world.
the gas used in welding is shielding gas
