Grade 7 4th Nine Weeks Exam 2025

What type of symbiosis?  Skunks often live in burrows that have been dug and abandoned by woodchucks.  

• commensalism
• mutualism
• parasitism
• predation

Refer to the diagrams of the Terrestrial Food Web and Marine Food Web. What do the two food webs have in common?

• They both contain omnivores.

• They both rely on photosynthesis.

• They both have carnivorous birds.

• They both have four levels of consumers.

A simple food chain is shown. According to the food chain, which would represent the flow of energy through this food chain?

• Producer → Decomposer → Consumer

• Consumer → Producer → Decomposer

• Decomposer → Producer → Consumer

• Producer → Consumer → Decomposer

The relationship between ticks and a dog can best be described as

• mutualism.

• competition.

• parasitism.

• commensalism.

Peacocks perform an elaborate dance while displaying their tail feathers. What purpose does this action most likely serve for the peacock?

• It keeps their feathers clean.

• It enables them to attract a mate.

• It allows them to more easily lose their feathers.

• It distracts other animals so the peacock can escape.

Which of these is an abiotic element of a desert ecosystem?

• sand
• cactus

• lizard

• insect

A scientist conducts an experiment to study the dynamics of a fish population. He observes two populations of a fish species at the same developmental stage, in two different artificial ponds of the same size having similar conditions. After a week, he raises the water temperature of one of the ponds to 30°C and maintains it over the next month. He counts the number of fish after a month in both the ponds. The results are shown in the table.

Refer to the table to left.

He concludes that a change in physical environment affected the population’s ability to reproduce. Which option supports this conclusion?

• The difference in the initial population and final population in Pond B.

• The varying environment in Pond B.

• The difference in the final populations of Pond A and Pond B.

• The constant environment in Pond A.

Changes to abiotic factors in an environment can impact biotic factors. Which statement is the BEST example of this situation?

• Heavy rainfall increases soil erosion.

• Melting glaciers cause sea levels to rise.

• Cold temperatures cause rocks to weather.

• Drought conditions increase competition among consumers.

Clown fish live among anemones, acting as a lure for the sea anemone's prey. The clown fish get protection and shelter from the anemone. This is an example of which type of symbiosis?

• Commensalism

• Mutualism

• Parasitism

Students kept some crickets in a classroom tank. The tank was kept in an area where it would get several hours of sunlight a day. The tank contained one area with water, and another area with soil where plants were growing. From which source did the crickets gain the energy they needed for cell processes?

• the soil

• the water

• the plants

• the sunlight