instruction:
In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.
question:
In humans , the pigmentation of the iris varies from light brown to black , depending on the concentration of melanin in the iris pigment epithelium ( located on the back of the iris ) , the melanin content within the iris stroma ( located at the front of the iris ) , and the cellular density of the stroma .
answer:
In humans , the pigment of the iris varies from light brown to black .

question:
Despite the tournament being an official iteration of the Copa Ame rica , the winner would not receive an invitation to the 2017 FIFA Confederations Cup due to the commemorative nature of the tournament , although eventual winners Chile had already qualified through their 2015 victory .
answer:
The winner of the tournament will not qualify for the 2017 FIFA Confederations Cup because Chile already won the 2015 Copa Ame rica .

question:
The combined oral contraceptive pill ( COCP ) , often referred to as the birth control pill or colloquially as " the pill " , is a type of birth control that is designed to be taken orally by women .
answer:
The combined oral contraceptive pill ( COCP ) is a contraceptive for women .