Explain how the substance inside a fluorescent tube changes when electrical charge is added to it

This energy causes a portion of the mercury in the tube to transition from a liquid to a gas state. During their journey down the tube, electrons and charged atoms will clash with the gaseous mercury atoms in certain instances. These collisions excite the atoms, causing electrons to jump to higher energy levels as a result of the excitation.

Explanation:

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organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.