Extract the answer to the question from the following context. Question: What do scientists believe to be the cause? Context: Scientists do not know the exact cause of sexual orientation, but they believe that it is caused by a complex interplay of genetic, hormonal, and environmental influences. They favor biologically-based theories, which point to genetic factors, the early uterine environment, both, or the inclusion of genetic and social factors. There is no substantive evidence which suggests parenting or early childhood experiences play a role when it comes to sexual orientation. Research over several decades has demonstrated that sexual orientation ranges along a continuum, from exclusive attraction to the opposite sex to exclusive attraction to the same sex.
Ans: a complex interplay of genetic, hormonal, and environmental influences

Extract the answer to the question from the following context. Question: When was the earliest time the term negar was used? Context: In the Colonial America of 1619, John Rolfe used negars in describing the slaves who were captured from West Africa and then shipped to the Virginia colony. Later American English spellings, neger and neggar, prevailed in a northern colony, New York under the Dutch, and in metropolitan Philadelphia's Moravian and Pennsylvania Dutch communities; the African Burial Ground in New York City originally was known by the Dutch name "Begraafplaats van de Neger" (Cemetery of the Negro); an early US occurrence of neger in Rhode Island, dates from 1625. Thomas Jefferson also used the term "black" in his Notes on the State of Virginia in allusion to the slave populations.
Ans: 1619

Extract the answer to the question from the following context. Question: What kind of contrast is seen in hard pines? Context: If a heavy piece of pine is compared with a lightweight piece it will be seen at once that the heavier one contains a larger proportion of latewood than the other, and is therefore showing more clearly demarcated growth rings. In white pines there is not much contrast between the different parts of the ring, and as a result the wood is very uniform in texture and is easy to work. In hard pines, on the other hand, the latewood is very dense and is deep-colored, presenting a very decided contrast to the soft, straw-colored earlywood.
Ans: very decided

Extract the answer to the question from the following context. Question: How do some of the past students still contribute to this day? Context: While Harkness' original colleges were Georgian Revival or Collegiate Gothic in style, two colleges constructed in the 1960s, Morse and Ezra Stiles Colleges, have modernist designs. All twelve college quadrangles are organized around a courtyard, and each has a dining hall, courtyard, library, common room, and a range of student facilities. The twelve colleges are named for important alumni or significant places in university history. In 2017, the university expects to open two new colleges near Science Hill.
Ans: colleges are named for important alumni