Analyze Word Choice Impact on Meaning Practice Test

Read this excerpt from a report about invasive species:

"In some lakes, zebra mussels hijack the food web by filtering huge amounts of plankton. Native fish that depend on plankton may struggle, while the water can become clearer in a way that hides the damage. Once established, the mussels cling to pipes and boat hulls, raising maintenance costs for towns and marinas."

What does the figurative word hijack mean in this context, and why might the author use it?

Read this excerpt from a lab write-up:

"Under the microscope, students observed onion root tip cells in mitosis. During prophase, the chromosomes condensed; during metaphase, they lined up at the cell’s center; and during anaphase, they separated toward opposite ends. Recording each stage helped students estimate how long the cell cycle spends in division."

Why does the author use the technical term mitosis instead of saying “cell splitting”?