Read the text below and answer question.
Will we ever grow replacement hands?
Over the past few weeks on the BBC News website we have looked at the potential for bionic body parts and artificial organs to repair the human body. Now we take a look at "growing-your-own".
There is a pressing need. A shortage of available organs means many die on waiting lists and those that get an organ must spend a lifetime on immunosuppressant drugs to avoid rejection.
The idea is that using a patient's own stem cells to grow new body parts avoids the whole issue of rejection as well as waiting for a donor.
Dr Anthony Atala, director of the Institute for Regenerative Medicine at the Wake Forest Baptist Medical Center in North Carolina, US, has made breakthroughs in building bladders and urethras.
• Flat structures, such as the skin, are the simplest to engineer as they are generally made up of just the one type of cell.
• Tubes, such as blood vessels and urethras, which have two types of cells and act as a conduit.
• Hollow non-tubular organs like the bladder and the stomach, which have more complex structures and functions.
• Solid organs, such as the kidney, heart and liver, are the most complex to engineer. They are exponentially more complex, have many different cell types, and more challenges in the blood supply.
"We've been able to implant the first three in humans. We don't have any examples yet of solid organs in humans because its much more complex," Dr Atala told the BBC.
Adapted from: http://www.bbc.co.uk/news/health-16679010 June 2012.
Analyze the following setence from the text:
“Solid organs, such as the kidney, heart and liver, are the most complex to engineer. They are exponentially more complex, have many different cell types, and more challenges in the blood supply.”
The expressions in bold print “the most complex” and “more complex” are examples of superlative and comparative structures. Select the alternatives that provide other examples of superlative and comparative sentences:
I. It has been selected as the best hospital in the state.
II. The treatment was highly expensive and extra medication was necessary.
III. The treatment is more effective on younger patients.
IV. Most of the time the effects of the medication are hard to notice.
