Refer to the Following Information to Answer the Questions Below

question 69

Multiple Choice

Refer to the following information to answer the questions below.
Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all.
-If doubly heterozygous SsNn cacti were allowed to self-pollinate, the F₂ would segregate in which of the following ratios?

• A)3 sharp-spined:1 spineless
• B)1 sharp-spined:2 dull-spined:1 spineless
• C)1 sharp-spined:1 dull-spined:1 spineless
• D)1 sharp-spined:1 dull-spined
• E)9 sharp-spined:3 dull-spined:4 spineless

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Definitions:

Air

The invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen.

Dysrhythmia

An irregularity in heart rhythm; also called arrhythmia.

Cardiac Output

The product of heart rate and stroke volume, measured in liters per minute; the amount of blood that is pumped by the heart in 1 minute.

Ventricular Fibrillation

A life-threatening heart rhythm that results in a rapid, erratic heartbeat, preventing the heart from pumping blood effectively.