Answer:
To avoid Hyper-oxygenation
Explanation:
Crucian carp have the ability to increase gill surface to maximize oxygen intake, or reduce overall area when under specif circumstances. If the fish does not need so much oxygen it will cover the protruding lamellae to reduce oxygen intake and avoid Hyper-oxygenation.
The Sahara is a desert located in northern Africa (as you can see in the map). And one of the only answer countries in proximity to that desert is Mali, so the answer would be C.
GDP is known as a lagging indicator.
Unemployment rate is also a lagging indicator.
Inflation is a lagging indicator.
Pretty sure National debt is not considered an economic indicator.
U.s is were they where born
