A survey was carried out to check the rampancy of substance abuse. during the course of the survey, one section of people volunt
eered their opinions willingly. the other section refused to confirm if they had or had not abused drugs and declined to take part in the survey. this survey suffers from ________.
The Natives have to use the trees for making houses and making pens for livestock. it is very bad for the rainforest and could disappear in a 5 million years to turn into grassland.
