Which term describes the way an organism responds to stimuli?

The term that describes the way an organism responds to stimuli is called behaviour.

Behaviour patterns may be simple or complex. Behaviour is explained through proximate causation and ultimate causation. In proximate causation, it is how behaviour works or ensues, internal state delivers physiologic basis, it is a study that determines physiologic changes like hormone levels. One example is a male songbird singing during mating season, this is because of the level of sex hormone-testosterone which binds to certain receptors in the brain which activates production of song. Ultimate causation on the other hand, explains why behaviour evolved through the years, it studies the behaviour in which it influences survival or reproduction. One example is a female bird during mating season who are mostly attracted by singing male birds and male songbirds have more offspring compared to those who don't influenced that shape behaviour.

Reflex Action is the term that describes the way an organism responds to stimuli. During reflex actions receptors are stimulated, they send signals to the central nervous system, where the brain co-ordinates the response. But sometimes a very quick response is needed, one that does not need the involvement of the brain. Reflex actions are rapid and happen without us thinking. For example, you would pull your hand away from a hot flame without thinking about it.

Ibelieve the answer is relative humidity  because it makes more sense that way. solar flares usually occur in space it doesn't affect the earth, well it could but it wont make a significant damage.  latitude is land it doesnt do anything. prevailing winds, i dont know the correct meaning for this but i doubt that affects the land so it has to be relative humidity.

The first means of speeding up reactions mentioned by the speaker is raising the enzymes