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JulijaS [17]
3 years ago
12

What is the last universal common ancestor?

Biology
1 answer:
SSSSS [86.1K]3 years ago
5 0

Answer:

The last universal common ancestor is the most recent population of organisms from which all organisms now living on Earth have a common descent, the most recent common ancestor of all current life on Earth.

Explanation:

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The ability to hunt others changes the fossil record. Why?
Virty [35]

Answer: its to overturn such resiliency

Explanation:

4 0
4 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
PLEASEEEEEE HELPPPPPP
nikklg [1K]

A. absolute

a. radioactivity

b. unstable atom

B. Atoms

1. atom

a. nucleus.

b. electrons.

2.proton

a. neutrons

b. isotopes

3. stable isotopes

a. radioactive isotopes.

b . radioactive decay.

c. parent isotopes.

d. daughter isotopes.

5 0
3 years ago
The nervous system is the major ______ system of the body.
strojnjashka [21]
Central nervous system. and automatically nervous system .it is mainly spinal cord system of the body.
5 0
4 years ago
How does a tree use photosynthesis to store carbon? ​
Effectus [21]

Answer:

A tree absorbs carbon during photosynthesis and stores it in the wood for the life of the tree.

Explanation:

I suggest visiting the website below for environmental science.

eartheasy.com

8 0
3 years ago
Read 2 more answers
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