The production possibilities frontier or curve: . A) indicates that any combination of goods lying outside the curve is attainable.
B) shows all goods and services that can be produced in an economy now and in the future.
C) separates all combinations of two goods that can be produced from those that cannot.
D) shows attainable combinations of two products that may be produced with available resources.

you can lose ranking 2 ways.

1) you don't have enough points due to you expending them by asking questions/your answers are deleted.

2) your brainliest's expired. this means that brainliests, once they exceed the 30 day limit, expires. this is to ensure that you continue to contribute into the community at a constant rank if you want to continue to have/exceed the rank you have right now.

if you go to profile, and click "show more information" located on the bottom left of the box with your information (on top of the questions answered, questions asked, and friends), you will be given the following information (example):

member since : 02/13/2017, 18: 11

questions answered: 9741

questions asked: 162

no. of brainliest answers: 1575

brainliest answers in last 30 days: 10

warnings: 0 view

questions/answers reported: 2637

questions/answers incorrectly reported: 64

look at the "brainliest answers in the last 30 days". this is the one that will affect your rank other than your points. again, once your brainliest expires (was earned 31+ days ago), it will not be counted.

~

by knowing conditionality

explanation:

the answer to this question would be shared investment