This was a very popular question. Although a few derailed by telling the story on how missionaries came into Nigeria, a good number were able to mention the relevant points and scored good marks. Those who scored highly were able to identify the following points:

Advantages
(i)  Christianity was introduced in many towns and villages;
(ii) Western education was introduced. Schools of different categories were established and products of the schools became teachers, catechists, nationalists, etc;
(iii)  the missionaries suppressed the traditional religion/practices and its negative influences such as cannibalism, human sacrifice, etc;
(iv)  the missionaries encouraged the use of English language as an official language and it became the 'lingua franca' in Nigeria;
(v)  they helped in the abolition of the slave trade;
(vi)  they promoted legitimate trade and majority of Nigerians participated and some played the role of middlemen between the Europeans and Nigerians;
(vii) they helped to translate some Nigerian languages into English e.g. Yoruba, Igbo;
(viii) they built hospitals, dispensaries and clinics.
(ix)  they introduced model farms for improved techniques on farming in certain places e.g. Abeokuta, Badagry, Lokoja;
(x) introduction of new architecture.

Disadvantages
(i)  traditional religion declined as a result of the activities of the missionaries;
(ii) they discouraged the practice of some of Nigeria's cherished cultures e.g. dances, songs, system of marriage, dresses, etc and this led to loss of interest in the culture;
(iii) they persuaded their home governments to dispossess the people of their land for the building of schools, medical centres and churches;
(iv)  the Nigerian chiefs and merchants lost the revenue from the slave trade;
(v)  the preaching of monogamy destabilized homes as new converts disowned their wives;
(vi) it led to conflicts between converts and their family members;
(vii)  it paved the way for the imposition of British colonial rule.