Swelling around the neck due to deficiency in iodine
lots of waste and dead leaves and things like that
dont plagarise ;)
I believe it is D. More African elephants today naturally lack tusks compared to the elephant populations 100 years ago, because big game hunters sought elephants for ivory.
Answer: Interventional Study
Explanation: When a treatment group is compared to standard (control) group it is called Interventional Study