Leticia timed how fast five apple slices turned brown (oxidate) after being being dipped in different preservatives such as lemon juice, fruit freshener, salt water and lime soda. another part of the experiment had the apple slices simply set out without any chemical on them. all parts of the experiment had the apple slices in the same indoor conditions such as humidity temperature and lighting; also only one variety of apple-red delicious was used.

Identify each of the following independent variable, dependent variable, constants, control experiment and repeated trials.