Many cell lines used in medical research were originally derived from cancerous tissue. Why are cancer cells often used for developing cell lines?

Which of the following are the level of biological structure at which stem cells play a part?     macromolecular level     cellular/ organelle levels     tissue/ organ level     organismal level     all of the above     none of the above ** select more than one if necessary, then for part 2, choose which of the following are NOT a level of biological structure?

How would you expect the mitotic index of a cancer tissue to compare with that of the onion root tip?

How does the concept of a stem cell differ between animal and plant systems?

What might best explain why the incidence of cancer increases as people age? Select one: a. mutations accumulate as people age b. cell division increases as people age c. protein synthesis increases as people age d. telomerase activity increases as people age e. ATP production increases as people age

A scientist is studying the genetic material that determines the traits of an individual. In which part of the cell must the scientist focus her studies?

what challenges can scientists encounter while cloning cells and using stem cells in tissue regeneration?