a. hydrogen
e. helium
a. hydrogen
b. oxygen
c. nitrogen
d. carbon
e. helium
e. helium
a. dark matter
b. dark energy
c. baryonic matter
d. neutrinos
a. hydrogen
e. helium
Hydrogen and helium are the most abundant types of baryonic matter in the universe.
One way to determine the abundance of baryonic matter in the universe is through studying the cosmic microwave background radiation (CMB). CMB is leftover radiation from the early stages of the universe and can provide valuable information about its composition.
According to observations and measurements, the two most abundant types of baryonic matter in the universe are hydrogen and helium. This finding is supported by the Big Bang theory, which explains that after the initial expansion of the universe, the first elements formed were hydrogen and helium.
Therefore, the correct answers are:
a. hydrogen
e. helium