Answer:
30
Explanation:
The seed of an angiosperm is formed as a result of fertilization (fusion of sperm in pollens and the ova from ovary). According to the question, the cells of the seed which will grow into the plant contains 20 chromosomes. Seeds of angiosperms contain a tissue called ENDOSPERM that forms as a result of the unique DOUBLE FERTILIZATION in angiosperms. It occurs when one haploid sperm cell fuses with two haploid polar nuclei to form a triploid endospermic structure that serves as food for the growing embryo in the seed.
Now based on the above explanation, the diploid plant cell with 20 chromosomes will have 10 chromosomes (half as much) in its gametes as a result of meiosis. This 10 chromosomes in each gamete (sperm and ovum) fuses to form a diploid zygote with 20 chromosomes, while one haploid sperm cell (10 chromosomes) also fuses with two haploid polar nuclei (10 chromosomes each) to form a triploid endosperm with 30 chromosomes i.e. 10+10+10.
They convert energy from food into energy the cell can use - Answer
Answer:
carbon dioxide- burning of fossil fuels
fluorinated gases- industrial processes
methane- production and transport of oil and natural
gas
nitrous oxide- agricultural and industrial activities
Explanation:
Greenhouse gases are gaseous components that induces greenhouse effect. This means that due to their structural ability to trap heat energy in the atmosphere, they contribute to the global warming effect on the Earth. However, this greenhouse gases are produced in large amounts as a result of the day-to-day anthropogenic activities. The following are the greenhouse gases and how they are produced.
Carbondioxide (CO2)- Carbondioxide is the most common and important greenhouse gas. It is generated via natural processes like respiration but also produced when fossil fuels e.g coal, petroleum etc. are burned.
Fluorinated gases- This is another greenhouse gas caused by activities of man. Fluorinated gases are produced in industries during the production of certain products.
Methane- Methane is a gaseous hydrocarbon and the principal constituent of natural gas. Therefore, the production and transportation of oil and natural gases can lead to the escape of methane into the atmosphere.
Nitrous oxide- Nitrous oxide is an oxide of nitrogen. It is mainly produced via agricultural processes such as nitrification and denitrification or use of fertilizers etc. and also industrial actions.
"A" bonds with "T", and "G" bonds with "C" (A-T) (G-C)
Answer:
The correct answer is B. The virus can infect the host.
Explanation:
- As the host and the virus both remain in the agar plate, the virus is capable of infecting the host cells.
- The host cell multiplies and grows by utilising the nutrient from the agar medium.
- After the virus particles infect the host, they replicate inside the host and produce new progeny virions which get released out of the host cell by killing it.
- The newly formed virions infect other host cells and the process continues.
- The killing of the host cells by the viruses result in the generation of clear zones on the agar plate which is also known as the zone of exclusion.
- In the zone of exclusion region, the host cells have been killed by the viruses.
