TASK DEFINITION: In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.
PROBLEM: Question: Plant cells have structures that animal cells? Answer: lack

SOLUTION: Plant cells have structures that animal cells lack.

PROBLEM: Question: Which single most factor is responsible for the extinction of hundreds of species of birds? Answer: human actions

SOLUTION: Human actions is responsible for the extinction of hundreds of species of birds.

PROBLEM: Question: What ensures that seeds germinate only when conditions for seedling survival are optimal? Answer: seed dormancy

SOLUTION:
Seed dormancy ensures that seeds germinate only when conditions for seedling survival are optimal.