Science P6 NHPS 2018 SA1 Q05

A garden was infested with bug X. The gardener carried out an experiment. He sprayed a similar amount of pesticide A on two similar potted plants in the garden with 100 bug X in each pot.The table below shows the number of bug X that died in each week.
Number of bugs that died
Pot 1Pot 2
Week 11516
Week 21412
Week 31310
Week 41110
What can be concluded from this experiment?