Explanation:

 The mode of worship was simple. The Vedic worship meant primarily only oblation and prayer. A great value was attached to the hymns. The Aryans chanted hymns to appease the various divinities. Yajna or sacrifice was another mode to appease the gods and goddesses. They offered milk, ghee, grains, wine, fruits etc. as offering into fire.
Animals like horses, buffaloes, rams, bulls, and even cows were also sometimes sacrificed. The process of sacrifice was simple. Every Aryan family took part in the offering of prayers and performing of fire-sacrifice. There was no priestly class for performing these religious sites. No shrine or temple was built. Image worship was unknown in those days.
The theory of reincarnation or rebirth was not completely formed. The Rig Vedic hymns had no consistent theory regarding life after death. The Rig Vedic idea of life after death was very vague. The soul departed to “Land of fathers”, pitralok was received by Yama and rewarded or punished according to its deeds. So the conception of rebirth was there.