yes.. yes they are
The balls are filled with gas and to ensure that they all have the same "bounce" they are kept in a fridge until use. Gas expands by heat.
Tennis balls that are kept at about 70 degrees and a low humidity will bounce higher on a given surface than balls kept at extremes of either environmental measure. Tennis balls used at professional tennis events are designed for the venue's specific surface, such that, for the most part, all will bounce equally high on their corresponding surface. Given that, a ball designed for a grass or clay court, will probably bounce higher on a hard court than a ball designed for a hard count.
Homemade pickles if kept in the fridge, can be kept for about 2 months. Store bought pickles if kept in the fridge, can be safely kept for about a year. Here's a good website to check out... www.stilltasty.com
cheese must be kept in a fridge otherwise it will go mouldy faster. if kept in a fridge, it will last for a while.
In a fridge. It is best to be kept in the fridge.
Chicken should always be kept in the fridge because 1000 peices of bacteria can be formed in 1 second if it is not kept in the fridge.
if you want to eat them they can be kept out of the fridge if not washed and last about a week and you should never put them in the fridge if you want to hatch them