Which example illustrates commensalism and not mutualism?

a) hippo dung is eaten by a large species of catfish native to african lakes. the catfish typically follow the hippo herds.

b) cattle have protozoa living in their gut that digest cellulose. the cows are able to feed on grass, while the protozoa are sheltered inside the cow.

c) oxpeckers remove parasitic fly larvae from the skin of buffalo. in exchange, they are protected from predatory cats, who will not challenge a buffalo.

d) ants 'farm' aphid insects like cattle. aphids suck the sap out of trees, which ants also feed on. in turn, the ants sting predators that attack the aphids.

What is a gene ? a) a section of a protein that codes for dna. b) the alternate version of a trait. c) the visible trait in the f1 generation. d) a section of dna that codes for a specific trait .

Sea levels are rising due to climate change while increasing numbers of people are moving into coastal areas. to accommodate more people, there has been increased construction of beachfront resorts and condominiums. how is this impacting sea turtle numbers and biodiversity and why? a. the increased human population in coastal areas has meant that more food is available to the turtles (e.g., dropped food, waste from restaurants), which has led to an increase in the numbers and diversity of sea turtles. b. there has been very little change in the numbers and biodiversity of sea turtles because the planet is so vast that they can simply relocate to less crowded beaches. c. this has resulted in a decrease in numbers and diversity of sea turtles because it is restricting available nesting sites, and hence reproduction. d. this has resulted in an increase in numbers and diversity of sea turtles because people are around to protect them from natural predators.

The human genome project is devoted to mapping the general dna sequence of our species. this could lead to the development of new medicines, as well as the possibility of using gene therapy to treat certain diseases. however, there are some ethical issues surrounding the mapping of individual genomes. one concern is a) that your genes may change over time, making the project useless. b) that insurance companies could discriminate based on genetic make-up. c) that since this has never been done before, we should probably not do it now. d) that sequencing our individual genomes is so expensive, it is a counter-productive strategy.