<u>Answer:</u>
The Earth has got its tilted axis and this is the reason for different seasons to be formed. Communities are a set of population found in that particular area and are of two types.
A) Terrestrial (Land)
B) Aquatic (Water).
These communities to flourish need a perfect environment with a perfect season. Hence according to the season formed due to the tilted axis influences the terrestrial community which forms in that particular region and have the ability for the region specific community growth.
The terrestrial community of a tundra or desert or rain forest all depends on the particular season that can be formed due to the position of the earth facing the sun.
Answer:
In the first level courses in human anatomy and the related health sciences, bone marks and bone features (including the proper terms for their description) are also important. To interact efficiently with practitioners interested in healthcare, science, forensics and related fields, it is important to be familiar with the language used for bone markings.
Answer:
From smallest to largest they are: Asteroid, planet, star, solar system, galaxy, and then universe
Explanation:
1. The correct answer is: The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane.
Binding and entering the host cell are the first steps of the HIV virus infection. So, these steps play a major role in determining the ability of HIV to degrade the human immune system. Binding of HIV to CD4+ T lymphocytes (express chemokine receptors CCR5 and CXCR4 called co-receptors) triggers the fusion of the viral and host cell membranes, initiating infection (viral core gets into the cytoplasm).
Attachment of the virion can be:
• Nonspecific-envelop protein of the virus (Env) binds to cell-surface heparan sulfate proteoglycans
• Specific-Env binds to integrin.
2. The correct answer is: Activation of the host cell by cytokines, growth factors, or antigens.
After the viral capsid enters the cell, single-stranded RNA genome is released from the attached viral proteins and copied it into a complementary DNA (cDNA) molecule thanks to an enzyme called reverse transcriptase. Next step is the integration of the viral DNA into the host cell's genome. This process is done by another viral enzyme called integrase. The integrated DNA is transcribed into RNA and then translated into proteins that will help the package of new viruse particles.
3. The answer is: false
Reverse transcriptase is an enzyme that catalyzes the formation of DNA from an RNA template. Since the genome of the virus (HIV) is single stranded RNA, reverse transcriptase copies it into a complementary DNA (cDNA) molecule. Thanks to this enzyme, formed cDNA can be integrated into host’s genome. Because of this proprety, antiretroviral drugs used to treat HIV infection work as reverse-transcriptase inhibitors.
Yes Limestone is a sedimentary rock. :)
