Answer:
(B) Energy transfer between trophic levels is almost always less than 20% efficient.
Explanation:
The ultimate source of energy on the Earth is the Sun. The energy coming from the Sun is captured by green plants by the photosynthesis. During photosynthesis sun energy is fixed into chemical energy (carbohydrate). So, in an ecosystem energy flow is unidirectional (from sun to the green plants). The fixed chemical energy from green plants is transferred to the herbivores then to carnivores through food. When one organism eats another organisms, only 10 % of the energy present in the organism is transferred as a food for the next organism and a large amount of energy is lost as heat into the environment. Thus, energy keeps on decreasing when stored energy moves from producers to top consumers. Thus, less than 20% energy transfer limits the trophic levels in most of the ecosystem.
Answer:
DNA is essentially a storage molecule. It contains all of the instructions a cell needs to sustain itself. These instructions are found within genes, which are sections of DNA made up of specific sequences of nucleotides. In order to be implemented, the instructions contained within genes must be expressed, or copied into a form that can be used by cells to produce the proteins needed to support life.
The instructions stored within DNA are read and processed by a cell in two steps: transcription and translation. Each of these steps is a separate biochemical process involving multiple molecules. During transcription, a portion of the cell's DNA serves as a template for creation of an RNA molecule. (RNA, or ribonucleic acid, is chemically similar to DNA, except for three main differences described later on in this concept page.) In some cases, the newly created RNA molecule is itself a finished product, and it serves an important function within the cell. In other cases, the RNA molecule carries messages from the DNA to other parts of the cell for processing. Most often, this information is used to manufacture proteins. The specific type of RNA that carries the information stored in DNA to other areas of the cell is called messenger RNA, or mRNA
Explanation:
In order to increase the rate of diffusion of materials in and out of the cell, the following modification can be done to the cell:
1. the shape of the cell can be changed to one that has high surface area to volume ration, for example sphere.
2.The cell can also divide into two in order to increase the surface area to volume ratio.
Answer:
C. The graph supports this theory, as it shows a gradual decline in populations of Adelie penguins.
Explanation:
Since Adelie penguins depend on ice to survive, a decline of ice would spell chaos for their survival. And coupled with the fact global warming means a bigger fluctuation of temperatures and a faster melting of ice on Earth, that would line up with the data of the decreasing Adelie penguins.
Hope this helped!
It's looks like the right answer looks like this: A ligand produces a response in a cell if it finds the right kind of a. receptor.
