Which types of baryonic matter are most abundant in the universe? Select the two correct answers.
carbon
hydrogen
nitrogen
helium
oxygen
hydrogen and helium
The two types of baryonic matter that are most abundant in the universe are hydrogen and helium.
To determine which types of baryonic matter are most abundant in the universe, we can refer to the concept of elemental abundances. Elemental abundance is a measure of the relative amount of each element in a given system, such as the universe.
One way to obtain information about elemental abundances in the universe is through observations of the cosmic microwave background radiation (CMB) and the measurements made by projects such as the Wilkinson Microwave Anisotropy Probe (WMAP) and the Planck satellite.
The two most abundant types of baryonic matter in the universe are:
1. Hydrogen: Hydrogen is the most abundant element in the universe, making up about 75% of the elemental abundance by mass. It is the primary fuel for star formation and plays a fundamental role in the formation of galaxies.
2. Helium: Helium is the second most abundant element in the universe, accounting for about 25% of the elemental abundance by mass. It is primarily formed during the early stages of the universe, through processes such as Big Bang nucleosynthesis and stellar nucleosynthesis.
Therefore, the correct answers are hydrogen and helium.