Answer:
Greenhouse gases from human activities are the most significant driver of observed climate change since the mid-20th century.1 The indicators in this chapter characterize emissions of the major greenhouse gases resulting from human activities, the concentrations of these gases in the atmosphere, and how emissions and concentrations have changed over time. When comparing emissions of different gases, these indicators use a concept called “global warming potential” to convert amounts of other gases into carbon dioxide equivalents.
Explanation:
Why does it matter?
As greenhouse gas emissions from human activities increase, they build up in the atmosphere and warm the climate, leading to many other changes around the world—in the atmosphere, on land, and in the oceans. The indicators in other chapters of this report illustrate many of these changes, which have both positive and negative effects on people, society, and the environment—including plants and animals. Because many of the major greenhouse gases stay in the atmosphere for tens to hundreds of years after being released, their warming effects on the climate persist over a long time and can therefore affect both present and future generations.
Answer:
Viral replication involves six steps: attachment, penetration, uncoating, replication, assembly, and release. During attachment and penetration, the virus attaches itself to a host cell and injects its genetic material into it.
A crevice is a narrow opening resulting from a split or a crack. <span />
Answer: etiolation of plant growth in shade, with fast growing cell without chloroplasts. Out of shade, cell differentiate again to produce photosynthesising cells
Explanation: It is a subjective decision as to what is ‘best’. Good examples are plant responses to changes in the nutrient supply.
when soil nitrogen is depleted some plants, such as legumes, grow nodules on their roots, with cells that release chemical signals to attract nitogen fixing bacteria.
Lack of light induces etiolation in many plants. New cells elongate and develop without chloroplasts, with rapid cell division exhibiting gravitropism, extending upward. When they grow beyond the shade area, cell differentiation changes again, to produce photosynthesising cells.
Answer:
1. Protect biodiversity
2. An indicator species
3. Biomagnification
4. Cutting down all the trees for lumber
5. Bioaccumulation
Explanation:
1. Conserving areas such as rain forests protect biodiversity because rain forests hold one of the highest biodiversity. They carry different types of resources that support different forms of life and at the same time, the organisms that live there support each other as well.
2. An indicator species is an organism that scientists can observe to see if there are changes in the environment it lives in. They judge the change or the implications based on the absence of the species in the environment (in which they used to be present), the presence of the species, and markers of adaptation due to the change in the ecosystem.
3. Biomagnification is a term used when contaminants that were consumed by the organisms in the lower trophic level are passed on to the next trophic level in higher concentrations. This is why those in the highest trophic levels are affected the most because they get the higher concentration of contaminants. DDT was banned when this phenomena was observed.
4. The greatest decrease in rain forest stability would be due to the cutting of trees. We can disrupt stability by gathering resources like nuts from some trees or when you remove one species of plant for medicine. However, the trees are an essential part of the rain forest because each part or area of the tree support different organisms. By cutting the whole trees off and several of them, you doom the organisms that rely on them as well.
5. As mentioned above, bioaccumulation is often interchanged with biomagnification but they differ in the usage of the terms. Like biomagnification, it talks about the accumulation of contaminants in organisms that ingest or absorb them. But bioaccumulation is a term used in a smaller scale, where it talks about the accumulation of the contimants in the tissues of the organism and not how they are passed on.
