In the observational study, the data provides a correlation between living close to the ozone hole and increasing one's chance of developing skin cancer. In the experimental study, where variables are directly manipulated and controlled, a relationship between exposure to higher levels of UV-B and contracting skin cancer is tested in mice.

CAUSE AND EFFECT

Explanation:

Cause and Effect is a relationship that is observed between two variables.

Cause is known as a independent variable while Effect is a dependent variable.

Cause is defined as a thing that allows a situation or incident to happen while,

Effect is defined as the aftermath or the evidence or impact of what has happened.

In the above question, the Cause( Independent variable) is known as the exposure of the skin to UV-B while the contracting of skin cancer is known as the Effect( dependent variable).

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation: