What where the weaknesses at fort moultrie which would make it’s very difficult?

The naval bombardment had little effect due to the sandy soil and the spongy nature of the fort's palmetto log construction. Careful fire by the defenders wrought significant damage on the British fleet, which withdrew after an entire day's bombardment.

Explanation:

- three-quarters or two-thirds..

- "the constitution provides that an amendment may be proposed either by the congress with a two-thirds majority vote in both the house of representatives and the senate or by a constitutional convention called for by two-thirds of the state legislatures."

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