In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.

[Q]: It consists of a bulb containing mercury attached to a glass tube of narrow diameter ; the volume of mercury in the tube is much less than the volume in the bulb .
[A]: The volume of mercury in the tube is much less than the volume in the bulb .

[Q]: Successive invasions of Germanic tribes finalized the decline of the Western Roman Empire in the 5th century , while the Eastern Roman Empire persisted throughout the Middle Ages , in a state called the Roman Empire by its citizens , and labelled the Byzantine Empire by later historians .
[A]: Successive invasions of Germanic tribes meant the end of the Western Empire in the 5th century , but the Eastern Empire persisted throughout the Middle Ages as the Byzantine Empire .

[Q]: Researcher Mark Changizi of Rensselaer Polytechnic Institute in New York has a more imaginative take on optical illusions , saying that they are due to a neural lag which most humans experience while awake .
[A]:
Researcher Mark Changizi of Rensselaer Polytechnic Institute in New York thinks optical illusions are due to a ' neural lag ' .