The Y chromosome does not cause color blindness. Colorblindness is a defective gene on the X chromosome. Females have 2 x chromosomes, thus one can serve as a backup for a defective gene. However, the Y chromosome in males is almost totally defective, thus does not have a backup.olorblindness is a defective gene on the X chromosome. Females have 2 x chromosomes, thus one can serve as a backup for a defective gene. However, the Y chromosome in males is almost totally defective, thus does not have a backup.
Kilwa Kisiwani (also known as Kilwa or Quiloa in Portuguese) is the best known of about 35 medieval trading communities located along the Swahili Coast of Africa.
Nairobi, city, capital of Kenya. It is situated in the south-central part of the country, in the highlands at an elevation of about 5,500 feet (1,680 metres). The city lies 300 miles (480 km) northwest of Mombasa, Kenyaâs major port on the Indian Ocean.