Answer:
Due to its formation in the supernova nucleosynthesis.
Step-by-step explanation:
The higher abundance of lighter elements in the universe than heavier elements occurs due to its formation in the supernova nucleosynthesis. The lighter elements such as hydrogen and helium are present in abundant amount and formed in supernova nucleosynthesis as compared to other heavier elements which are formed through other events. The lighter elements occupy less volume and space as compared to heavier elements which is also a reason for their abundance.