Speak slowly please, this is for a group of ESL students :)))
A pygmy is a member of an ethnic group whose average height is unusually short; many anthropologists define pygmy as a member of any group where adult men are on average less than 150 cm tall. The term is often associated with peoples of Central Africa, such as the Aka, Efé and Mbuti. If the term pygmy is defined as a group's men having an average height below 1.55 meters, then there are also pygmies in Australia, Asia and South America.
Various theories have been proposed to explain the short stature of pygmies. Some studies suggest that it could be related to adaptation to life in the darkness of the rainforests where little vitamin D or calcium can limit bone growth. Other explanations include lack of food in the rainforest environment, low calcium levels in the soil, the need to move through dense jungle, adaptation to heat and humidity
This is great :) Thank you so much.