3. According to the reading, the writer argues that the university extend the broadcasting hours of its radio.
The woman thinks it is not a good idea for two reasons.
First, the radio is not a major source of information for most students. Instead students use the university's website to search for significant announcement or information. So current situation about the radio hours do not need to be modified.
Second, students do not rely on the radio for entertainment. To be specific, almost every students enjoy watching TV or listening to music between classes. So even if the university offers more fun radio, students would still spend their time going online for lots of contents.
For these reasons, she believes that extending the broadcast hours of the radio is not a good idea.
4. According to the reading, warning coloration results when animals use the color to alert predators.
The professor explains this concept by giving two examples.
First, he describes that monarch butterfly has a conspicuous marking on its wings. When birds consume this butterfly, they become sick and vomit. Then they realize that they have to avoid eating this butterfly. So when predators like birds observe the butterfly's marking, they do not approach this butterfly.
Second, he describes that blue-ringed octopus uses its bright blue-ring to alert predators when it feels threatened. Even bite from this octopus can be fatal to even larger organisms. So when predators recognize the octopus's blue ring, they avoid coming close to the octopus.
These examples demonstrate the warning coloration.
5. The man's problem is that he lost essential research note for the presentation and do not have time to research the material again.
The woman and man suggest two possible solutions. The first suggestion is to attend a seminar that deals with the same topic. The second suggestion is to change the order of the presentation with other students.
I think the first suggestion is better for him. This is because the seminar would reduce lots of time to prepare presentation. If he misses the seminar, he would have to squeeze in lots of time for research. Also it's not certain that he will be able to switch his spots in presentaion's order with others.
For these reasons, I would recommend the first option for him.
6. The professor explains how weed can be beneficial to the soil by giving two examples.
First, he describes that weeds can prevent soil loss caued by soil erosion. To be specific, in traditional agiculutral practice, some part of soil are kept bare. So when it rains, lots of topsoil are lost. But when weed covers the bare ground, the soil erosion do not occur because the weed's root hold the soil together.
Second, he describes that weeds enrich and fertilize the soil. Most weeds have a deep taproot that play a role in bringing up nutrients to the surface. Moreover, when people plant the weeds into the soil, they break down into compost which provides lots of nitrogen to plants.
These two examples illustrate how weeds can help the soil to be in better condition.