Question

it is fair to say that determining if something actually causes cancer is a tricky business. which statement best describes a major reason why finding a causal (pronounced cause - al) relationship is so hard.
because we cant test on animals.
because cancer only stems from one or two factors and peoples lives are pretty simple.
because very little is known about cancer and how it works.
because treating a patient with an unknown carcinogen and waiting to see if they get cancer is unethical.
true or false: the first line of defense from uv raci tion is the layer in your skin that contains melanocytes.
true
false

Explanation:

1. For the first question, testing potential carcinogens on humans by exposing them to unknown carcinogens and waiting for cancer to develop is highly unethical, which is a major hurdle in establishing causal relationships. We can test on animals (so the first option is wrong), cancer is caused by multiple factors (ruling out the second option), and a lot is known about cancer (eliminating the third option).
2. For the second question, the layer of skin with melanocytes (the epidermis - specifically the basal layer) is the first - line defense against UV radiation as melanocytes produce melanin which absorbs UV light.

Answer:

1. Because treating a patient with an unknown carcinogen and waiting to see if they get cancer is unethical.
2. True