Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

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Study for the Biology STAAR Test. Improve your skills with flashcards and multiple choice questions, each question is accompanied by hints and explanations. Prepare for success!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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Which of the following describes an abiotic factor?

Plants in an ecosystem
Soil composition
Animals that inhabit an area
Microorganisms in water

The correct answer is: Soil composition

Abiotic factors are the non-living components of an ecosystem that influence the environment and the organisms within it. Soil composition is a key abiotic factor because it refers to the mineral content, texture, pH, and organic matter that affect plant growth and, consequently, the entire ecosystem. The properties of soil impact water retention, nutrient availability, and the types of vegetation that can thrive in a given area. Understanding soil composition helps to explain how it supports life, as it is crucial for plant health and, subsequently, for the animals that depend on those plants for food. In contrast, the other choices refer to biotic factors, which are living components of ecosystems. Plants, animals, and microorganisms are all classified as biotic factors because they are living organisms that interact with one another and their environment.