Mountain barriers cause what is known as the "orographic effect". true or false?

it's True

Explanation:  Mountains have two major effects called the orographic effect, which causes clouds and precipitation to form on one side of the mountain, and the rain shadow effect, which is a drier area on the opposite side of the mountain

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Yes

Explanation:

Mountains cause the orographic effect, therefore mountain barriers cause the same thing. Orographic effect is caused when air masses that are low down suddenly get forced upwards to a high elevation. This causes a lot of rain on the side of the mountain facing the wind.

1-5 2-7 3-4

explanation:

a is the answer i believe.