Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
Caffeine cause dose dependent prominent increase in force of contraction and period of contraction of muscle
<u>Explanation:</u>
Caffeine is widely used in foods and drinks. Its long time use can effect central nervous system include lethargy memory, sleep disorder and anxiety.
Increase in concentration of calcium ion will result increase number of power stroke and force for contraction. However latent period and relaxation period are unaffected by caffeine. Increase in concentration of calcium ion will result increase number of power stroke and force for contraction.
Because of calcium ion release in skeletal muscle, caffeine causes peripheral manifestation such as hyper-reflexia, muscle twitching etc.
High amount of caffeine leads to increase in release of Ca2+ from sarcoplasmic reticulum. It increases tension development in single tetanic contraction and re-initiate maximum tension in fatigue single myofibre by restoring Ca2+ release from sarcoplasmic reticulum to non-fatigued levels.
Answer:
It is true that one-toed horse of today steadily evolved from its five-toed ancestor.
Explanation:
- Evolution is the law of nature.There is a continuous process of evolution in each biological species in nature.
- Similarly, horses had 5 toes millions of year back, but according to the theory of gradualism their use decreased and toes started fusing.
- Now, its only one toe at present but the vestigial left over provides the solid evidence for the fact that horses had 5 toes in the past.
In terms of processing in the nervous system, the reactio<span>n was faster for the more simple tasks because it required less processing and therefore small amount of neurons had to travel through out nerve system because our frontal lobe had less delay since there was less to think about.</span>
