Answer: TWO.
At least two groups: treatment group and control group.
The treatment group is that is exposed to the different levels of the independent variable ( a medication for example), while the control group is not treated, so the researchers can compare the effect of the medication.
5 is 2 I’m not sure about 4 though....
Yes. Everything is made up of mass. If it takes up space, it has mass
Answer:
poisoning, breathing problems, skin rashes, allergic reactions, allergic sensitisation, cancer, and other health problems from exposure.
Explanation:
many hazardous chemicals are also classified as dangerous goods.
