Why pH level test is important in lotion testing? Why it matter? Explain your answer

The ph value of the skin plays an essential role in protecting the skin.

Explanation:

An acidic protective layer is crucial for the functioning of the skin's protective barrier. Neutralizes aggressive alkaline substances (eg, aggressive surfactants), inhibits bacterial growth and restores and maintains an optimal acidic environment in which natural flora can develop.

If there is a rise in the ph value of the skin, the nature of the skin may become disturbed. Essential epidermal lipids can no longer be synthesized, so in this case, the skin loses and dries. By breaking its protective function, the skin can become dry, sensitive, or extremely

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.