They are more similar then different. Animal and plant cells have some of the same cell components in common including a nucleus, Golgi complex, endoplasmic reticulum, ribosomes, mitochondria, peroxisomes, cytoskeleton, and cell (plasma) membrane. The main difference is that plant cells have a cell wall while animal cells only have a cell membrane. In addition, plant cells preform photosynthesis, while animal cells preform cellular respiration.
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Answer:
Scientist 1
Explanation:
<em>The conclusion of scientists 1 is valid.</em>
Human activities such as burning of fossil fuels, agriculture, deforestation, etc. leads to the emission of carbon in the form of carbon dioxide into the atmosphere. <em>An increase in the population of a city will only lead to an increase in these activities and hence, an increase in the amount of carbon emitted into the atmosphere.</em>
Also, volcanic activities leads to the production of volcanic gases which is a mixture of carbon dioxide, oxides of sulfur, nitrogen, etc.
<u>However, an active volcano that is several miles away from the city might not be a major source of carbon in the air above a large city. The carbon dioxide produced from such volcanic activity thins out before reaching the city.</u>
Answer:
The fewer number of T cells a person has, the more chances to be affected by an opportunistic infection. When the number of T cells reaches 200 cells/µl, the person is at risk of being infected by other infections.
Explanation:
The whole immune system of a person who is infected with HIV infection seems to be severely affected. When the person is not treated or the disease is in a very advanced stage, the depletion of the T- cells turns to be very sharped, especially CD4+ T cells. At this point, the immune system can not resist the attack of other microorganisms. The <em>lower is the number of CD4+ T Cells, the higher possibility the person has to be attacked by opportunistic infections. </em>
Classically, it has been suggested that opportunistic infections appear after the CD4 + T lymphocytes reach very low levels, such as 200 cells/µl. The number of circulating T cells can be used as an indicator and a measure of global "immune competence", and the previously mentioned amount of CD4 + T cells is an accepted universal reference used to predict the risk of having one of these opportunistic infections.
Body temperature, Environmental temperature, Body mass, Reproductive condition, Activity, Feeding, Body condition, Season. All of these would help increase it. Hope this helps. :)