GENE FLOW - natural movement of alleles through the gene pool of a population
GENETIC DRIFT - random chance events that influence the gene pool (has a larger effect on small populations) - E.g., a group of birds migrates to an island but then a storm happens and then get stuck on the island to start a new population (founders effect - they've drastically decreased the gene pool and represent a minority of the initial population)
BIOTECH - literally any tool that we use that utilises living organisms - usually for agriculture or industry (artificial pollination, artificial insemination, selective breeding, SCNT cloning, BT cotton, Golden Rice, Gene cloning via recombinant plasmids, vaccines, etc etc)
Usually a question will ask how a named biotech will influence the biodiversity of a population: to answer this we talk about how (for example) by using artificial insemination to breed two cows that are on opposite sides of the farm, biodiversity is initially increased, because new alleles are being combined and bred to increase gene flow. However, if the same cow's gametes are used to inseminate an entire population, biodiversity drastically decreases because the gene pool is being over saturated with one specific set of alleles, and the offspring population may be more succeptable to being wiped out by a single selection pressure (as they have a common set of genes)
HOPE THAT HELPS
also people correct me if I'm wrong or made any slight errors or I can fix my responses