How Have Classification Systems for Living Things Changed Over the Years

question 36

Multiple Choice

How have classification systems for living things changed over the years?

• A) Scientists have always recognized five kingdoms of living things, but the placement of species within those kingdoms has changed.
• B) Until the last 20 years, organisms had been classified first as animal or plant. Recently, a five-kingdom system became the preferred classification system.
• C) The three-domain system has been introduced within the last 30 years, to supplement the five-kingdom system.
• D) The exact organization proposed in the eighteenth century by Carl Linnaeus has recently been reinstituted by scientists.

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Definitions:

Fovea

A small, central pit in the retina of the eye responsible for sharp central vision, essential for activities where visual detail is of primary importance, like reading and driving.

Receptor Cells

Specialized cells which detect and respond to external or internal stimuli, converting them into signals that can trigger specific responses.

Night Vision

The ability to see in low-light conditions, often enhanced through the use of night vision equipment or naturally adapted vision in some animals.

Rods

Photoreceptor cells in the retina of the eye that are sensitive to low light levels and are important for night vision.