Some are different experiments so theres no right answer.
so that they will stay fresh for as long as you want.
it can stay fresh for 2 weeks
Apples and other fresh fruit
Keep them in the fridge and away from moldy foods :)
It will stay fresh for some hours. Not too long. So it depends how long the fridge been off. Too long is bad.
cod will stay fresh forever if you freeze it in a air tight bag.
Forever
i would say brownies stay fresh for about 3-5 days if they are in a sealed container.
Weed stays fresh for a long time. You can put it in a plastic bag to keep it fresh for a long time or you can also freeze it.
It depends what kind, please be more specific. Here is a tip that might help you: The less longer they stay in there, the better and never defreeze and then refreeze food, it is bad for you. Hope it helps.
two days
i don't think it will help the lifespan of the flowers