The idea that even if something is out of sight, it still exists is called
egocentrism
object permanence
conservation
reversibility

Object Permanence

Explanation:

Object permanence is the understanding that objects continue to exist even when they cannot be perceived (seen, heard, touched, smelled or sensed in any way).

Note: Is a stated information.

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.

answer is b shrapnel injuries