Apologetics, a theological science which has for its purpose the explanation and defense of the Christian religion. In defining apologetics as a form of apology, we understand the latter word in its primary sense, as a verbal defense against a verbal attack, a disproving of a false accusation, or a justification of an action or line of conduct wrongly made the object of censure. Quite different is the meaning now conveyed by our English word, “apology”, namely, an explanation of an action acknowledged to be open to blame. For this reason, the adoption of the word, “Apologetics”, in the sense of a scientific vindication of the Christian religion is not altogether a happy one. Some scholars prefer such terms as “Christian Evidences”, the “Defense of the Christian Religion“.
Its aim is to give a scientific presentation of the claims which Christ’s revealed religion has on the assent of every rational mind; it seeks to lead the inquirer after truth to recognize, first, the reasonableness and trust-worthiness of the Christian revelation as realized in the Catholic Church, and secondly, the corresponding obligation of accepting it.
From the records of the Apostles and their immediate successors is set forth the institution of the Church as a true, unequal society, endowed with the supreme authority of its Founder, and commissioned in His name to teach and sanctify mankind; possessing the essential features of visibility, indefectibility, and infallibility; characterized by the distinctive marks of unity, holiness, catholicity, and apostolicity. These notes of the true Church of Christ are then applied as criteria to the various rival Christian denominations of the present day, with the result that they are found fully exemplified in the Roman Catholic Church alone.
(Source: Catholic Encyclopedia)

Always be ready to give an explanation to anyone who asks you for a reason for your hope, but do it with gentleness and reverence, keeping your conscience clear, so that, when you are maligned, those who defame your good conduct in Christ may themselves be put to shame. (1 Peter. 3:15-16).
Do you not believe that I am in the Father and the Father is in me? The words that I speak to you I do not speak on my own. The Father who dwells in me is doing his works. Believe me that I am in the Father and the Father is in me, or else, believe because of the works themselves. Amen, amen, I say to you, whoever believes in me will do the works that I do, and will do greater ones than these, because I am going to the Father. (John. 14:10-12).
I too have decided, after investigating everything accurately anew, to write it down in an orderly sequence for you, most excellent Theophilus, so that you may realize the certainty of the teachings you have received. (Luke. 1:3-4).
The apostles Barnabas and Paul tore their garments when they heard this and rushed out into the crowd, shouting, “Men, why are you doing this? We are of the same nature as you, human beings. We proclaim to you good news that you should turn from these idols to the living God, ‘who made heaven and earth and sea and all that is in them.’ (Acts. 14:14-15).