Please respond to the following questions.

These are also found in the "For Further Thought" sections of your textbook.

1. The success of an organ transplant depends on many factors. What unavoidable factor would diminish the chance of success of a lung transplant, but is not a factor at all in a heart transplant?

2. At a construction site, a hole caved in and buried a workman up to his shoulders in wet sand.

The foreman told the trapped man that a crane would be there in 20 minutes to pull him out, but another worker said they couldn't wait, and had to dig NOW. He was right. Why is this a life-threatening emergency?