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Julli [10]
3 years ago
12

The Cambrian explosion was

Biology
1 answer:
tangare [24]3 years ago
8 0

Answer:

It was the sudden appearance (over a 10my period) of many different organisms, which occurred approx 540-548 mya. ... So it can be away from sources of oxygen, preventing microorganisms from decomposing the organism.

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Having curved or straight thumbs is thought to be a Mendelian trait, and the
leonid [27]

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considering the straight allele is dominant then the curved thumb allele must be recessive. so,if someone has two recessive alleles they will express that characteristic. Therefore, the person's thumbs would be curved

8 0
2 years ago
Explain the interaction that occurs between a t-helper lymphocyte and a b cell when the b cell is being induced to produce peanu
Paraphin [41]

Answer:

           According to Dr. Ray Schiling (member of the American Academy of Anti-aging medicine) about 1.5 million people suffer from peanut allergies. The seeds of peanut (<em>Arachis hypogea</em>) contain an array of allergens that can induce the production of IgE specific antibodies predisposed individuals. Ara1 and Ara2 are most common seed storage protein that cause allergy. Other allergen proteins such as Ara3 to Ara 17 have also been identified that cause allergy.  


Entry of peanut allergen into body

When peanut allergens enter the body of an individuals it leads to development of different symptoms like itchy skin, tingling sensation, nausea, runny nose and anaphylaxis.  

Allergic response

There are two subsets of T-cells Th1 and Th2. Both invoke different response to allergens. Th1 direct a non-allergic response while Th2 direct allergic response ranging from releasing of histamine to anaphylactic response. The presence of IL-12 cytokines direct a Th1 based, nonspecific response.  


Mechanism of allergic response (interaction between helper T cell and B cell)

Step 1.  

           When allergen enter to body they are encountered by B cells. Immunoglobulin receptors on the surface of B cells recognize antigen (Peanut allergens) and get attached, which are then internalized and processed. Within B cells the fragments of antigens combine with HLA class 2 proteins.  

Step 2

             HLA class 2 with antigen fragments (peanut allergens) then display on the surface of B cells.

Step 3

            Receptors on the surface of helper T cells recognizes the complex of HLA class 2 and antigen fragments (peanut allergen) and is activated to produce cytokines, which activate the B cells.  

Step 4

             B cell is activated by cytokines and begins clonal expansion. Some of the progeny become anti-body producing plasma cells while other become memory B cells.  


7 0
3 years ago
What is the term for an observable trait of an organism??
babymother [125]
I believe the term for an observable trait of an organism would be called or noted as the organism's phenotype.
7 0
4 years ago
An experiment looking at structures smaller than a cell would most likely employ a _______.
Evgesh-ka [11]
 A microscope is the answer.
7 0
4 years ago
Read 2 more answers
NEED HELP ASAP:
Anni [7]

Answer:

A but i might be wrong

Explanation:

7 0
3 years ago
Read 2 more answers
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