STAAR Review 2024 8th Science

Explain the concept of ecosystem competition.

• Competition in an ecosystem occurs when organisms vie for the same resources, such as food, space, or mates.

• Ecosystem competition is when organisms cooperate to share resources effectively.

• Competition in an ecosystem is solely about territorial disputes among species.

• Ecosystem competition refers to the mutual benefits organisms gain from living together.

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What is the difference between short-term and long-term events?

• Short-term events occur quickly and have immediate effects, while long-term events develop over time and have lasting impacts.

• Short-term events are always negative, while long-term events are always positive.

• Short-term events are planned, while long-term events are spontaneous.

• Short-term events have no impact, while long-term events affect only a few people.

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What is the difference between a stable isotope and an unstable isotope?

• Stable isotopes undergo radioactive decay, while unstable isotopes do not.

• Stable isotopes do not undergo radioactive decay, while unstable isotopes do and can emit radiation.

• Stable isotopes are heavier than unstable isotopes.

• Unstable isotopes are found only in nature, while stable isotopes are man-made.

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What is an isotope?

• A variant of a chemical element with the same number of protons and different numbers of neutrons.

• A type of chemical bond between two elements.

• An element that has lost or gained electrons.

• A molecule that contains two or more different elements.

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What is urbanization and its impact on the environment?

• Urbanization is the process of increasing population in urban areas, which can lead to habitat destruction and increased pollution.

• Urbanization refers to the decline of rural areas and the growth of agricultural land.

• Urbanization is the movement of people from cities to rural areas, resulting in less pollution.

• Urbanization is the process of building more parks and green spaces in urban areas.

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What is the atomic number of an element?

• The number of protons in the nucleus of an atom.

• The total number of electrons in an atom.

• The number of neutrons in the nucleus of an atom.

• The mass of an atom measured in atomic mass units.

How does a reduction in the snail population affect competition in an ecosystem?

• It decreases competition between wood mice and shrews due to more available resources.

• It increases competition between wood mice and shrews due to fewer available resources.

• It has no effect on competition among species in the ecosystem.

• It leads to a decrease in the overall biodiversity of the ecosystem.

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What is the role of decomposers in an ecosystem?

• Decomposers break down dead organic material, returning nutrients to the soil and supporting plant growth.

• Decomposers produce energy through photosynthesis for plants.

• Decomposers consume living plants and animals to obtain energy.

• Decomposers create new organic material from inorganic substances.

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What human activity has caused the greatest increase in polluted runoff?

• Illegal dumping.

• Agricultural runoff.

• Industrial waste discharge.

• Urban development.

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What is runoff in environmental science?

• The process of water evaporating from soil and plants.

• The flow of water, usually from precipitation, that moves across the ground and can carry pollutants into water bodies.

• The absorption of water by soil and plants.

• The collection of water in lakes and rivers after rainfall.

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