What was the phrase that was coined by herbert spencer to describe only the fittest societies surviving over time

"survival of the fittest"

Explanation: Herbert Spencer coined the phrase, "survival of the fittest." Spencer wrote "survival of the fittest," which imply that those who were most fit would survive the social world due to some biological mechanism that made them superior.

no , per capita income is not a true measure of the development because: -it only tells us about average income not how income is distributed among the people.it only give us an idea of the economic aspect.it is only at the qualitative basis.moreover, income is not only the way of development other factors are also as much as important as income.