Penny and nikki were assigned a lab activity to test the effectiveness of different stain removers. they took four shirts and stained each shirt with grape juice. each shirt was treated with a different stain remover per the directions on the bottle. after washing each item, they came to the conclusion that stain remover b was the best of the four for removing stains. if you were their science teacher, what advice would you give them to them better validate their findings? a) none. the experiment and conclusion were perfect. b) use fewer shirts and fewer stain removers. they tried to do too muchc) their conclusion should be specific to grape juice on that particular fabric. d) they should use something besides grape juice, because it is not a popular drink.

C) Their conclusion should be specific to grape juice on that particular fabric.

Explanation:

Experimental design should be capable of testing a hypothesis. With Penny and Nikki experiment (with one type of fabric and one type of pigment) can only answer the effectiveness of different stain removers to remove grape juice pigments from the specific fabric that was utilized. If they wanted to test the effectiveness of different stain removers, they should use different pigments and various types of fabrics. Different chemicals (active ingredients in stain removers) can have a different effect on different pigments or on different types of fabrics.

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.