Bees collect nectar from apple blossoms while carrying pollen between flowers, increasing pollination. What symbiotic relationship do the bees and apple trees have?

Cattle egrets eat insects stirred up by grazing cattle, while the cattle are not measurably helped or harmed. How is this relationship classified?

A tick feeds on a white-tailed deer's blood, reducing the deer's available nutrients. Which type of symbiosis is this?

Mycorrhizal fungi receive sugars from a plant's roots and increase the plant's uptake of water and mineral nutrients. What is this interaction?

Orchids grow on tall rainforest trees, gaining access to sunlight without taking nutrients from the trees. What relationship do the orchid and tree have?

Mistletoe penetrates a host tree's tissues and takes water and dissolved minerals, lowering the tree's growth. Which interaction is shown?

Clownfish gain shelter among sea anemone tentacles, and the anemone receives nutrients from clownfish waste and protection from some predators. What is this relationship?

Barnacles attach to a whale and are carried to productive feeding waters; the whale is not helped or harmed. Which symbiosis type applies?

A tapeworm absorbs digested food from a human intestine, leaving fewer nutrients for the human. How should this relationship be classified?

In a restored prairie, legumes house nitrogen-fixing bacteria in root nodules. The bacteria gain carbohydrates, and the plants gain usable nitrogen. What is this?

A small fish follows a shark and eats scraps from its meals, with no demonstrated effect on the shark. Which relationship is this?

Parasitic wasp larvae develop inside a caterpillar and consume its tissues, eventually killing it. What type of interaction is this?

Cleaner shrimp remove parasites and dead tissue from a reef fish, and the fish avoids infection while the shrimp gets food. What relationship is this?

A burrowing owl uses an abandoned prairie dog burrow for shelter after the prairie dog has left; the prairie dog is unaffected. Which symbiosis type is shown?

A flea feeds on a dog's blood. What effect does the flea have on the dog?

Lichens contain a fungus and a photosynthetic alga or cyanobacterium. What does the photosynthetic partner provide to the fungus?

A remora clings to a sea turtle with a suction disk on its head. What benefit does the remora receive?

In a mycorrhizal association, what does the plant receive from the fungal partner?

A brood parasite lays eggs in another bird's nest, and the host bird raises the parasite's chick. What cost does the host bird experience?

A flowering plant provides nectar to a hummingbird. What benefit does the plant receive when the hummingbird visits several flowers?

A mosquito feeds on a human. What does the mosquito gain from this interaction?

Oxpeckers perch on a rhinoceros and eat the ticks on its skin. What benefit does the rhinoceros receive?

A whale carries barnacles to areas with plankton-rich water. In this commonly cited example, what does the whale receive from the barnacles?

A parasitic plant attaches special roots to a host shrub's water-carrying tissue. What is the immediate effect on the host shrub?

A honeybee gathers nectar from a flower and transfers pollen. Why is this mutualism rather than commensalism?

A tick becomes engorged after feeding on a mammal. Why is this parasitism rather than predation?

A bromeliad grows high on a tree branch and uses the branch only for support. Why is this not parasitism?

Cleaner fish eat parasites from larger fish. Which description correctly distinguishes this from herbivory?

A cowbird egg hatches in a warbler nest, and the warbler feeds the cowbird chick. Why is this parasitism rather than commensalism?

A remora travels with a shark and eats scraps, but studies show no consistent effect on the shark. Which statement best distinguishes this from mutualism?

A fungus receives sugar from plant roots and provides phosphorus to the plant. Why is this not parasitism?

A leech feeds on a turtle's blood. Which observation would support classifying the interaction as parasitism instead of commensalism?

A fig species is pollinated only by one wasp species, and the wasp can reproduce only inside that fig. The wasp disappears locally. What is the most likely result for the fig?

After antibiotic use eliminates many beneficial gut bacteria, a person has difficulty digesting some foods. What does this outcome show about the human-bacteria relationship?

A crop loses its bee pollinators after nearby habitat is converted to pavement. What is most likely to happen to fruit production in bee-pollinated plants?

A host animal is treated successfully for a heavy tapeworm infection. What is the most likely immediate effect on the host's nutrient availability?

A forest tree loses most of its mycorrhizal fungi after soil is heavily disturbed during construction. What is a likely result for the tree?

A whale population leaves an area, so barnacles that depended on whales for transport no longer have that transport. What is the likely effect on the barnacles?

A grazing mammal population declines sharply, and cattle egrets no longer find insects flushed by the animals. What is the likely effect on the egrets?

A conservation project removes a parasitic wasp from a greenhouse crop. What is the most likely short-term result for caterpillars that the wasp larvae had used as hosts?