Extract the answer to the question from the following context. Question: Alleles are different variants of what objects? Context: Genes can acquire mutations in their sequence, leading to different variants, known as alleles, in the population. These alleles encode slightly different versions of a protein, which cause different phenotype traits. Colloquial usage of the term "having a gene" (e.g., "good genes," "hair colour gene") typically refers to having a different allele of the gene. Genes evolve due to natural selection or survival of the fittest of the alleles.
Ans: Genes

Extract the answer to the question from the following context. Question: If a goose were feeling tired in the sky, how would it want to avoid traveling? Context: Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 12–20% of the energy they would need to fly alone. Red knots Calidris canutus and dunlins Calidris alpina were found in radar studies to fly 5 km/h (3.1 mph) faster in flocks than when they were flying alone.
Ans: fly alone

Extract the answer to the question from the following context. Question: What changes did nubians make around 500 BC? Context: During the Neolithic Era, before the onset of desertification, around 9500 BCE the central Sudan had been a rich environment supporting a large population ranging across what is now barren desert, like the Wadi el-Qa'ab. By the 5th millennium BCE, the people who inhabited what is now called Nubia, were full participants in the "agricultural revolution", living a settled lifestyle with domesticated plants and animals. Saharan rock art of cattle and herdsmen suggests the presence of a cattle cult like those found in Sudan and other pastoral societies in Africa today. Megaliths found at Nabta Playa are overt examples of probably the world's first known archaeoastronomy devices, predating Stonehenge by some 2,000 years. This complexity, as observed at Nabta Playa, and as expressed by different levels of authority within the society there, likely formed the basis for the structure of both the Neolithic society at Nabta and the Old Kingdom of Egypt.
Ans: living a settled lifestyle with domesticated plants and animals

Extract the answer to the question from the following context. Question: Who were the first to play Christmas music marathons? Context: These Christmas music marathons typically start during the week before Thanksgiving Day and end after Christmas Day, or sometimes extending to New Year's Day. Afterwards, the stations usually resume their normal music fare. Several stations begin the holiday format much earlier, at the beginning of November. The roots of this tradition can be traced back to the beautiful music and easy listening stations of the 1960s and 1970s.
Ans: easy listening stations