Context: Most cotton in the United States, Europe and Australia is harvested mechanically, either by a cotton picker, a machine that removes the cotton from the boll without damaging the cotton plant, or by a cotton stripper, which strips the entire boll off the plant. Cotton strippers are used in regions where it is too windy to grow picker varieties of cotton, and usually after application of a chemical defoliant or the natural defoliation that occurs after a freeze. Cotton is a perennial crop in the tropics, and without defoliation or freezing, the plant will continue to grow.

Question: How is most cotton harvested?
Answer: mechanically

Question: What is the cotton harvesting machine that removes the boll with damaging the plant?
Answer: cotton picker

Question: What machine strips off the entire head of the cotton plant?
Answer: cotton stripper

Question: What weather conditions mandate the planting of stripper types of cotton?
Answer: windy

Question: What type of plant is cotton?
Answer: perennial

Question: How are most plants harvested?
Answer: Unanswerable

Question: What is the cotton harvesting machine that removes the bolll and damages the plant?
Answer: Unanswerable

Question: What machine strips off the chemicals off the cotton plant?
Answer: Unanswerable

Question: What weather conditions mandate the planting of defoliation types of cotton?
Answer: Unanswerable

Question: What type of plant is defoliant?
Answer: Unanswerable