How can the prevailing rate of species extinction be declined by 30% solely through protection of biodiversity hotspots?

Assume that the chances of a patient having a heart attack is 40%. It is also assumed that a meditation and yoga course reduce the risk of heart attack by 30% and prescription of certain drug reduces its chances by 25%. At a time a patient can choose any one of the two options with equal probabilities. It is given that after going through one of the two options the patient selected at random suffers a heart attack. Find the probability that the patient followed a course of meditation and yoga?

Can you think of a situation where we deliberately want to make a species extinct? How would you justify it?

From a waterfall 60 m high, water falls at a rate of 27 m^3*s^(-1) . If 75% of energy is available at the bottom for use , how much power will be generated ? Mass of 1m^3 of water is 10^3 kg . If the power is used to lift water from a 180 m deep tubewell, how much water can be raised in 1 s?