Gene S Controls the Sharpness of Spines in a Type

question 49

Multiple Choice

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. If doubly heterozygous SsNn cactuses 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:

Instability

A situation characterized by a lack of stability, predictability, or consistency, often leading to chaos or disorder in social, economic, or political contexts.

Truman Doctrine

A U.S. foreign policy established in 1947, asserting that the U.S. would provide economic and military aid to countries threatened by communism, marking the start of the Cold War era containment strategy.

Mr. X Article

The Mr. X Article, also known as "The Sources of Soviet Conduct," was an influential 1947 essay written by George F. Kennan under the pseudonym "Mr. X," outlining the strategy of containment of Soviet expansion.

Containment Doctrine

A foreign policy strategy aimed at preventing the spread of communism by providing economic and military aid to countries threatened by Soviet expansion.