Q. The terms ‘Event Horizon’, ‘Singularity’, `String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of

Answer: (a) Observation and understanding of the Universe

The Standard Model of particle physics is the theory describing three of the four known fundamental forces (electromagnetic, weak and strong interactions – excluding gravity) in the universe and classifying all known elementary particles.
It was developed in stages throughout the latter half of the 20th century, through the work of many scientists worldwide, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks.
Since then, proof of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.

A singularity refers to a place in the universe where our laws of physics simply break down.
The term first came into popular use in Albert Einstein’s 1915 Theory of General Relativity. In the theory, a singularity describes the center of a black hole, a point of infinite density and gravity within which no object inside can ever escape, not even light.

The event horizon is a boundary that marks the outer edge of black holes. It is the point at which nothing, not even light, can escape.
Because light can’t escape, black holes themselves neither emit nor reflect it, and nothing about what happens within them can reach an outside observer. But astronomers can observe black holes thanks to light emitted by surrounding matter that hasn’t yet dipped into the event horizon.