Human skin pigmentation is controlled by multiple genes. What is necessary for the normal development of pigmentation? The genes
must be arranged in sequence on the DNA strand. The genes must be arranged into an operon. The genes must be regulated by a single enhancer sequence. The genes must share the same control element.
The answer is; The genes must share the same control element
When multiple genes are expressly coordinately, this is referred to as synexpression. Such genes are expressed in coordination either because they code for protein subunits of a complex protein or their gene products are required in stoichiometric amounts.
An independent variable is the only variable that is changed while the rest is kept the same. In this setup, the doctor is using different creams on the same patient with the same skin condition so the independent variable is the skin cream and not the skin condition.
