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]: To make this possible , in most cases the two valves are articulated using an arrangement of structures known as hinge teeth ( often referred to collectively as the " dentition " ) .
[A]: To make this possible , the two valves usually have hinge teeth ( the " dentition " ) .


[Q]: The earliest clear statement of how chromosomes may spread in a population not because of their positive fitness effects on the individual organism , but because of their own " parasitic " nature came from the Swedish botanist and cytogeneticist Gunnar O ̈ stergren in 1945 .
[A]: The Swedish botanist and cytogeneticist Gunnar O ̈ stergren in 1945 noted how chromosomes may spread in a population because of their own ” parasitic ” nature .


[Q]: Space Shuttle " Endeavour " ( Orbiter Vehicle Designation : OV-105 ) is a retired orbiter from NASA 's Space Shuttle program and the fifth and final operational Shuttle built .
[A]:
Space Shuttle Endeavour ( OV-105 ) is the fifth space shuttle run by NASA .