In animals like Annelids, Molluscs, organs have associated to form functional systems, each system concerned with a specific physiological function. This pattern is called ________ system level of organization.
The average revenues of 7 consecutive years of a company is Rs 71 lakhs. If the average of first 4 years is Rs 66 lakhs and that of last 4 years is Rs 78 lakhs. What is the revenue for the fourth year.