Decreasing the overall volume of the gases in a nebula would prevent nuclear fusion.
Explanation:
A nebula refers to a huge cloud of gas and dust in space. Some nebulae arise from the gas and dust withdrawn due to the explosion of a dying star like a supernova. Other nebulae are the locations where the novel stars are starting to get produce. Due to this, some nebulae are also known as star nurseries. The reduction in the entire volume of gases mainly hydrogen could inhibit the nuclear fusion in the nebula.
S-S Overlapping. In this kind of overlapping, one 's' orbital from each participating atom undergoes head-on overlapping along the internuclear axis. ...