Biology grade 9

What is a food chain?

• A type of exercise equipment

• A series of organisms each dependent on the next as a source of food.

• A popular fast food restaurant

• A method of preserving food

Answer explanation

A food chain is a series of organisms that depend on each other for food.

How does a food web differ from a food chain?

• A food web is a diagram of different types of food, while a food chain is a type of necklace made of food.

• A food web shows multiple interconnected food chains, while a food chain only follows one path of energy and nutrients.

• A food web is a type of spider web that catches food, while a food chain is a type of restaurant.

• A food web is a type of cooking technique, while a food chain is a type of exercise equipment.

Answer explanation

A food web shows multiple interconnected food chains, while a food chain only follows one path of energy and nutrients.

What does a pyramid of numbers represent?

• A pyramid of numbers represents the number of organisms at each trophic level in a food chain or web

• A pyramid of numbers depicts the geographic distribution of species within an ecosystem

• It represents the population density of organisms but does not reflect their energy roles

• A pyramid of numbers illustrates the average lifespan of organisms in different ecosystems

Answer explanation

A pyramid of numbers represents the number of organisms at each trophic level in a food chain or web.

Name the primary source of energy.

• Sun

• Water

• Coal

• Wind

Answer explanation

The primary source of energy is the Sun. It provides heat and light, and is essential for life on Earth.

Explain the concept of trophic levels.

• Trophic levels are hierarchical levels in an ecosystem that classify organisms based on their feeding relationships.

• Trophic levels are determined by the size of the organisms in an ecosystem.

• Trophic levels are related to the temperature of an ecosystem.

• Trophic levels are based on the age of the organisms in an ecosystem.

Answer explanation

Trophic levels classify organisms based on feeding relationships in an ecosystem.

What is the pathway of energy flow?

• From the moon to producers, then to consumers and decomposers

• From the earth to producers, then to consumers and decomposers

• From the stars to producers, then to consumers and decomposers

• From the sun to producers, then to consumers and decomposers

Answer explanation

Energy flows from the sun to producers, then to consumers and decomposers.

Provide an example of a grazing food chain.

• Tree -> Squirrel -> Hawk -> Rabbit

• Grass -> Grasshopper -> Frog -> Snake

• Seaweed -> Shrimp -> Fish -> Shark

• Wheat -> Mouse -> Owl -> Fox

Answer explanation

In a grazing food chain, energy flows from grass to grasshopper to frog to snake. This is the correct choice.

How is a food web constructed?

• By creating a list of all the animals in the area

• By drawing a map of the ecosystem

• By connecting multiple food chains together

• By using bricks and cement

Answer explanation

A food web is constructed by connecting multiple food chains together.

What is a chemical reaction?

• A chemical reaction is a process in which one or more substances are converted into one or more different substances.

• A chemical reaction is a process in which substances remain unchanged

• A chemical reaction is a process in which substances disappear

• A chemical reaction is a process in which substances turn into energy

Answer explanation

A chemical reaction is a process where substances are converted into different substances.

Define activation energy.

• The energy released during a chemical reaction

• The energy required to stop a chemical reaction

• The energy stored in chemical bonds

• Minimum amount of energy required to start a chemical reaction

Answer explanation

Activation energy is the minimum amount of energy required to start a chemical reaction.