In an experiment, a control is used to establish a baseline to compare the results of the main experiment to. Having a control group rules out any environmental variables, such as temperature and... In an experiment, a control is used to establish a baseline to compare the results of the main experiment to. Having a control group rules out any environmental variables, such as temperature and...
Knives, including small pocket knives, are only allowed in checked bags. Only plastic and round-tip butter knives are allowed as carry-on blades. Most bladed items are allowed in checked baggage, including scissors, razors, swords, axes, box cutters and blade tools, if they are properly wrapped or sheathed.
Items packed in dry ice are accepted in carry-on or checked baggage provided they are properly wrapped/packed to protect against leakage, then placed in a box, carton or container that: 1  is properly vented to allow for the release of carbon dioxide gas, 2  is in good condition and free of any damage.