TASK DEFINITION: Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.
PROBLEM: Sentence1: Here, the lungs supply the blood with oxygen. 
Sentence2: Brain cells die quickly if their blood supply is cut off.

SOLUTION: blood

PROBLEM: Sentence1: harming an animal species has a negative impact on the population size of that species. 
Sentence2: Pesticides have a negative impact on the population size of a species.

SOLUTION: impact

PROBLEM: Sentence1: Flowers attract pollinators, and fruits encourage animals to disperse the seeds. 
Sentence2: Poinsettia flowers can also be a problem.

SOLUTION:
Flowers