The primary source of energy in most ecosystems is/are (1 point)
heterotrophs. autotrophs. the sun. glucose.
autotrophs.
Which would be an autotroph in a grassland ecosystem? (1 point)
muskrat
prairie cordgrass mallard duck monarch butterfly
prairie cordgrass
Which of the following best explains why there are fewer secondary consumers than producers? (1 point)
Secondary consumers have less cell processes that need energy.
More secondary consumers can absorb radiant energy from the sun.
Heat energy given off from producers kills off primary and secondary consumers.
Around 10% of the energy is transferred to support the next trophic level.
Around 10% of the energy is transferred to support the next trophic level.
Which trophic level ingests the most biomass in order to receive the energy they need? (1 point)
primary consumers tertiary consumers producers
secondary consumers
primary consumers
Wolves were reintroduced to Yellowstone National Park in 1995. They began to hunt the abundant elk population, so elk numbers decreased. The elk carcasses provided food for other predators, like foxes, coyotes, and bears, so all of their populations increased. Elk used to overgraze on willow plants; now that willows are growing back, beaver numbers are increasing, because they prefer the slow-moving water that willows cause.
Which of these species is a keystone species?
(1 point)
bears elk wolves willows