This occurs when environmental factors interact with genetic factors to produce traits. The term multifactorial means many factors. Traits that involve multiple genes and complicated patterns of inheritance are said to be exhibiting multifactorial transmission.

because it have two clases of genes involved: oncogenes and tumor suppressor genes

homosexual

Health as a multifactorial phenomenon involves several factors. These factors include economic, socio-cultural, and environment. It also includes political factors which involve political will and empowerment.

neither, it is a birth defect