If frank is using a drug that causes addiction in nearly 75% of those who use it, he is probably ingesting

Crack

If frank is using a drug that causes addiction in nearly 75% of those who use it, he is probably ingesting crack.

Crack is a relatively cheap, extremely addictive form of cocaine which is usually smoked through a crack pipe. Crack is highly used and available in a rock form that is usually white, cream, tan, or light brown. Crack is extremely concentrated and addictive. It is  possible for an individual  to become addicted to it after its first use. When crack is smoked, its effects take place under a minute and lasts within 30 to 60 minutes.

if the hares very faster than they are now, and thus the lynx's hunting success rate drops because it will be harder to catch them, the rate that will change will be the pray-rate. the pray-rate will change because more hares will be able to survive, thus more individuals for reproduction, so the end result will be increasing population of hares.

the predator-rate will remain pretty much the same because there will be more than enough pray, but the hunting success rate is stagnant.