Directions: Read the passage given below carefully and then answer the following questions that follow 

The Big Bang Theory is the ___(1)___ cosmological model of the observable universe from the earliest known periods through its subsequent large-scale evolution. The model describes how the universe expanded from an initial state of high density and temperature and offers a ___(2)___ explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background (CMB) radiation, and large-scale structure.
Crucially, the theory is compatible with Hubble–Lemaître law — the observation that the farther away galaxies are, the faster they are moving away from Earth. ___(3)___ this cosmic expansion backward in time using the known laws of physics, the theory describes an increasingly concentrated cosmos preceded by a singularity in which space and time lose meaning (typically named "the Big Bang singularity"). Detailed measurements of the universe's expansion rate place the Big Bang singularity at around 13.8 billion years ago, which is thus considered the age of the universe.
After its initial expansion, an event that is by itself often called "the Big Bang", the universe cooled ___(4)___ to allow the formation of subatomic particles, and later atoms. Giant clouds of these primordial elements – mostly hydrogen, with some helium and lithium – later coalesced through gravity, forming early stars and galaxies, the ___(5)____ of which are visible today. Besides these primordial building materials, astronomers observe the gravitational effects of an unknown dark matter surrounding galaxies.