I would say 1 and 4 are the best answers. GMO crops are clones (genetically identical) so it reduces the genetic diversity making crops susceptible to new diseases.
When have the intentions to analyze the sea floor an try to measure the difference of materials present on the seafloor we woulds see or analyze that if we are moving away from the land outwards into the deep down ocean then we would see the sequence of the in the following way continental shelf - continental slope - abyssal plain.
