Does darker skin color make it easier to live under sun?

Yes it does.

Human skin is composed of three layers: the epidermis, dermis, and fat. Cells in the epidermis (the outermost skin layer) called melanocytes produce melanin the pigment that gives skin and eyes their color. The more melanin is produced, the darker the skin color.

Melanin helps protect the skin against effects of the sun such as skin cancers  and premature aging. In African American skin, melanin provides a sun protection factor (SPF) equivalent to 13.4 compared to 3.4 in white skin and thus the former have lower incidences of skin disorders associated with exposure to the sun.

the median of the data is 4.5.

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]