How can subsidence lead to the formation of sedimentary rock?

Subsidence changes the base level allowing further sedimentation. Augmented burial results in ever cumulative heat and pressure as the sediments are compressed. For sandstones, the augmented pressure of compaction outcomes in heaviness solution of the quartz grains. The silica unconfined from this procedure forms quartz overgrowths inside the pores efficiently cementing the sand grains together. If the procedure lasts, the sandstone will finally form quartzite.

Yes that is correct answer in 6

Water flows along the east coast and across the western tropical pacific towards south america, while they both are directed towards that way,  el niño does not directly affect the southern flow of water along the coast.