During elimination training the positive reinforcement should be given after the proper behavior is exhibited?

Could someone me with number one you

The asian shore crab (hemigrapsus sanguineus) is an invasive species that has impacted the atlantic coast. predict what characteristic of this invader would most likely disrupt the biodiversity of this area.

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures