<u>Answer:</u>
<em>Dark rich organic material formed as a top layer in soil from the decayed remains of plants and animals is called humus. </em>
<u>Explanation:</u>
When dead parts of plants and animals are deposited in soil the <em>decomposing bacteria present in the soil act on these remains and break them down. </em>
Plant and animal bodies contain organic compounds which are broken down into inorganic nutrients by the decomposers. These nutrients are taken up by producers and the nutrients restart their journey in the food chain.
<em>Humus is identified by its rich dark color. The amount of humus decides how fertile the soil is. More the humus content fertile is the soil. </em>
Large molecules such as hormones materials are expelled from cells during exocytosis
<u>Explanation:</u>
The materials inside the cells are transferred to the outside of the cell and this manner is termed as Exocytosis. This method is termed as a kind of active transport since it needs energy for this transformation process. One of the major purposes of this process is to discharge trash matters like hormones and proteins.
For a cell to cell transmission and chemical signal messaging these methods are essential. Proteins that are newly generated are transferred to the peak of the plasma membrane by exocytosis. There are three general pathways of exocytosis.
This is an example of CONDOMINANCY.
Condominancy is said to occur when two different alleles are combined together to form a different allele, in which the alleles are expressed equally and none of them is dominant. In the example given above, the black rat population mated with the white rat population to produce offspring that are grey in colour. Thus, the white and the black colour of the parents are not dominant, but are equally expressed to give gray colour.
Answer:
Virulence, the capacity to cause disease, varies markedly among viruses. Some viruses cause lethal disease while others do not. For example, nearly all humans infected with rabies virus develop a disease of the central nervous system which ultimately leads to death. In contrast, most humans are infected with circoviruses with no apparent consequence.
Explanation: One explanation for viral virulence is that it facilitates transmission. However, a comparison of infections caused by two enteric viruses, poliovirus and norovirus, does not support this general view. Both viruses infect the gastrointestinal tract and are spread efficiently among humans by fecal contamination.
