90) The three leading petroleum producing countries in correct descending order are:

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Saudi Arabia, U.S.(A) and Russia

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In progressive waves, the amplitude may be constant and neighboring points are out of phase with each other

In air or other gases, a progressive anti node occurs at a displacement node and a progressive node occurs at a displacement anti node

Longitudinal wave can be polarized while transverse wave cannot be polarized

Transverse wave can be polarized while longitudinal wave cannot be polarized

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Answer is:

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