Answer and Explanation:
Observing population directly gives you accurate result .
Direct observation does not need any intermediary as they themselves go for survey.
So, it is cost efficient.
Whereas indirect observing may involve manipulations.
It requires someone or many to hire who helps in surveying.
It incurs cost.
Thus, direct observation is always better than indirect observation.
Explanation:
a living system is a system in an organism consisting of organs. each organs carry out different functions to ense life processes can be carried out effectively. The function of the organs are determined by the cells which make up the tissues. The connections are important to remove wastes/toxins out of the body and help absorb nutrienys, in some cases produce hormones as a form of homeostasis to ensure the body remains in a healthy optimised state constantly.
Circulatory and Respiratory systems working together to provide body with oxygen.