The most suitable one-word substitute of the following words:-
(a) a group of people who have come together in a religious building for worship and prayer
(b) the scientific study of animals, especially their structure
1
(a) Cortege, (b) Heliotherapy
2
(a) Caucus, (b) Demography
3
(a) Congregation, (b) Zoology
4
(a) Shoal, (b) Genealogy