Answer: Economic
Explanation:A streak is something that characterizes somebody - an element of somebody's character that practically defines them.
So, a drinking streak refers to a person who has a drinking problem; a gambling streak refers to someone who gambles a lot; a mean streak is a bad and a mean person; and a funny streak is a humorous person.
I have a bad habit of chewing on my finger nails
it forms covalent bonds by sharing electrons
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.