Before a pea flower opened, Mendel cut away its pollen-bearing parts, then dusted its stigma with pollen he had collected from a plant of his own choosing. What did this step let him do?

Mendel began each experiment with lines that had produced nothing but tall offspring, or nothing but short offspring, for several generations of self-pollination. Why did he start this way?

Rather than reporting which kind of plant was common in a generation, Mendel counted every single offspring plant and recorded the number of each kind. What did this practice make possible?

Mendel chose pea traits that came in two sharply different forms, such as round versus wrinkled seeds and purple versus white flowers, rather than traits like overall vigor. Why was this choice important?

After a cross between two true-breeding lines gave offspring that all looked alike, Mendel let those offspring pollinate themselves and grew the seeds. What was the purpose of this further step?

Mendel crossed a true-breeding tall pea line with a true-breeding short one. Every plant in the resulting generation was tall, and none was of middling height. What does this uniform result show?

In Mendel's second generation for plant height, he counted 787 tall plants and 277 short ones. What does this result show?

Mendel put pollen from tall plants onto short plants, and in a second cross put pollen from short plants onto tall ones. Both crosses gave nothing but tall offspring. What does this pair of results show?

Mendel crossed a hybrid plant grown from yellow seeds with a plant grown from green seeds. About half the offspring had yellow seeds and about half had green ones. What does this show about the hybrid?

Mendel crossed plants that were hybrid for both seed shape and seed color. Among 556 seeds he counted 315 round yellow, 108 round green, 101 wrinkled yellow and 32 wrinkled green. What does this show?

Mendel let the tall plants of his second generation pollinate themselves. About one third of them produced only tall offspring, while the other two thirds produced both tall and short offspring. What does this show?

In a pea plant that carries two unlike factors for seed shape, each pollen grain it forms ends up with just one of the two factors, never with both. Which of Mendel's laws does this describe?

In a pea plant carrying two unlike factors for pod color and two unlike factors for plant height, which pod-color factor a gamete ends up with has no bearing on which height factor it ends up with. Which law is this?

A pea plant carries one factor for purple flowers and one for white. Its flowers are purple, and they look no different from those of a plant that carries two purple factors. Which of Mendel's ideas does this show?

A tall pea plant was allowed to pollinate itself, and some of its offspring were short even though the plant itself was tall and had been grown in the same conditions as all the rest. Which of Mendel's laws accounts for this?

Suppose two pea traits were followed for generations and the offspring only ever showed the same two pairings of the traits that the original parents had, with no new combination ever appearing. Which law would this pattern fail to follow?

Mendel crossed two purple-flowered pea plants with each other and the offspring were 705 purple and 224 white. What must have been true of the two parents?

A tall pea plant was crossed with a short one. About half the offspring were tall and about half were short. Shortness is recessive. What were the two parents?

A tall pea plant was crossed with a short one and every one of the many offspring was tall. Shortness is recessive. What must have been true of the tall parent?

A cross between two pea plants gave offspring in a ratio of about 9 round yellow to 3 round green to 3 wrinkled yellow to 1 wrinkled green. What must have been true of the two parents?