How may congress propose a constitutional amendment?

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.

dirty, contaminated water

contaminated food,

chlostrophobic living spaces,

mice infestation,

etc,

one of the major compromises in the constitutional convention was between the small states and big states. the small states wanted each state to have the same number of representatives in congress. the big states wanted representation based on population.