## Free Response

Describe one of the reasons why the garden pea was an excellent choice of model system for studying inheritance.

## Hint:

The garden pea is sessile and has flowers that close tightly during self-pollination. These features help to prevent accidental or unintentional fertilizations that could have diminished the accuracy of Mendel’s data.

How would you perform a reciprocal cross for the characteristic of stem height in the garden pea?

## Hint:

Two sets of P_{0} parents would be used. In the first cross, pollen would be transferred from a true-breeding tall plant to the stigma of a true-breeding dwarf plant. In the second cross, pollen would be transferred from a true-breeding dwarf plant to the stigma of a true-breeding tall plant. For each cross, F_{1} and F_{2} offspring would be analyzed to determine if offspring traits were affected according to which parent donated each trait.

Mendel performs a cross using a true-breeding pea plant with round, yellow seeds and a true-breeding pea plant with green, wrinkled seeds. What is the probability that offspring will have green, round seeds? Calculate the probability for the F_{1} and F_{2} generations.

## Hint:

Since we are calculating the probability of two independent events occurring simultaneously, we use the product rule.

F_{1} generation: Since green seed color is recessive, there is a 0% probability that any plants in the F_{1} generation will have green, round seeds.

F_{2} generation: The probability of growing an F_{2} generation plant with green seeds is ¼, while the probability of growing an F_{2} generation plant with round seeds is ¾. We can use the product rule to then calculate the probability of a plant with green, round seeds:

Calculate the probability of selecting a heart or a face card from a standard deck of cards. Is this outcome more or less likely than selecting a heart suit face card?

## Hint:

A standard deck of cards contains 52 cards, 13 of which are hearts and 12 of which are face cards.

Heart suit **or** face card: This calculation requires the sum rule since there are multiple pathways to successfully pulling a desired card.

The probability of selecting a heart suit or a face card is significantly more likely than the probability of selecting a heart suit face card ($3/52=5.8\%$).