The universe as we know it is home to several galaxies, planets and stars. Hydrogen and helium were the most abundant elements present in the early universe. Heavier elements like carbon, oxygen, phosphorus and even metals were later formed through various fusion reactions in stars.
Nevertheless, matter makes up only 5% of the universe. Nearly 95% is referred to as 'dark matter' which is a subject of research in many scientific communities.
Ans a) 5%