Hydrangea macrophylla shrubs produce flowers that can range in color from blue to pink. Th… — SAT

Hydrangea macrophylla shrubs produce flowers that can range in color from blue to pink. This color variation is determined by the availability of aluminum ions in the soil, which the plant requires to synthesize its blue pigment. In highly acidic soils, typically with a pH of $5.5$ or lower, aluminum is soluble and easily absorbed by the root system, resulting in blue flowers. In contrast, in neutral to alkaline soils with a pH of $6.5$ or higher, aluminum becomes chemically insoluble and cannot be taken up by the plant. Which choice most logically completes the text?

A
hydrangea shrubs grown in highly acidic soils will grow larger and produce more flowers than those grown in neutral soils.
a hydrangea shrub grown in soil with a pH of $7.0$ will be unable to absorb aluminum and will therefore produce pink flowers.Cevap
C
neutral soils naturally contain much lower amounts of aluminum than acidic soils do.
D
hydrangea shrubs require pink pigment to facilitate the absorption of aluminum from the soil.

Cevap

A hydrangea shrub grown in soil with a pH of

7.0

will be unable to absorb aluminum and will therefore produce pink flowers.

The correct option logically follows from the text because a pH of

7.0

falls into the range of

6.5

or higher, where aluminum is insoluble and cannot be absorbed by the plant. Since aluminum absorption is necessary to synthesize blue pigment, a plant grown in these conditions will be unable to produce blue flowers, resulting in pink flowers.

Adım Adım Çözüm

Identify the soil conditions and pH threshold for aluminum solubility and absorption.

In soils with a pH of

5.5

or lower, aluminum is soluble and absorbed (leading to blue flowers), while in soils with a pH of

6.5

or higher, aluminum is insoluble and cannot be absorbed (leading to pink flowers).

This establishes the relationship between soil pH, aluminum availability, and flower color.

Evaluate the condition of a hydrangea grown at a pH of

7.0

A pH of

7.0

falls into the category of

6.5

or higher (neutral to alkaline).

This allows us to determine the state of aluminum in the soil at this specific pH level.

Deduce the resulting flower color based on the chemical state of aluminum.

At a pH of

7.0

, aluminum is insoluble and cannot be taken up, preventing the synthesis of blue pigment and resulting in pink flowers.

This completes the logical chain from the premises in the text to the conclusion.

Anahtar Kavram

Drawing logical conclusions based directly on conditions and constraints stated in the text.

Soru

Cevap

Adım Adım Çözüm

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