matter of opinion
You could say a plethora of activities. You could go on dictionary.com for more synonyms.
you are about to live on Mars.
Time, which could be used for more productive activities, is wasted.
Dangerous habits such as abortion, drug use, infertility and more. These activities most often destroys the womb thereby making conception difficult.
SecreTs.
so they could have more fun time and not get in trouble
The opposite could be to make more difficult or complex, which is to complicate.
read your power point.
It sneaks up on you gradually if you habitually overeat and just makes physical activities more and more difficult with any extra weight you put on. and people make fun of you
Insiders
It is difficult to say without more information. Factors like their activities, observations of the island, and changes in their surroundings could help estimate the time passed.