1. In the mid-seventeenth century, Dutch scientist Jan Baptista van Helmont struggled to understand where plants get the material that allows them to grow larger. He planted a willow tree of a given weight in a ?xed quantity of soil and then, ?ve years later, weighed both the willow and the soil. He found that the tree had gained 164 pounds during the period but that the soil had lost very little weight. His conclusion was that the willow’s weight gain came solely from the water it absorbed through its roots. If you could be transported back to van Helmont’s time, what would you tell him about the source of the willow’s weight gain?

2. Compare and contrast the three modes of photosynthesis. List the advantages and disadvantages of each mode.

3. Cystic fibrosis is a disease caused by a recessive allele, and so it appears only as a homozygous recessive genotype. Two parents without cystic fibrosis have a child who does have the disease. Explain what happened and include a Punnett square in your answer. (You can use a word-processor table with three columns and three rows to draw the Punnett square, and watch out for automatic capitalization. If your word-processor cannot draw a table, then describe what is in each cell of the table.)

4. How did the phrase “dumb jock” come to be? (This is a rhetorical question.) The phrase reflects two characteristics, intelligence and athletic prowess. Let us suppose that above average intelligence occurs in 25 out 100 children and superior athletic prowess occurs in 1 out 50 children. Using the rules of multiplication or addition, calculate the odds on a person having above average intelligence AND athletic prowess.

5. List the four basic tissue types and provide a brief definition of each.

6. Explain what causes hair to lose its color, that is, go gray as we age.

7. Name the three phases of early embryonic development, and relate what happens in each phase.