Discovery In 1928 it was discovered by Frederick Griffith in an experiment generally known as transformation.
Experiment
In his experiment he considered two strains of <em>streptococus pneumonia,</em> one was R-type which was non-virulent and cause no disease in mice, other was virulent and S-type which cause disease and at last death of mice.
This experiment was comprised of four steps which are as follow:
Step 1: First he injected living strain of S into mice, after sometime mouce died.
Step 2: He injected living strain of R into mice, the mice alive as he did not got any disease.
Step 3: He injected heat killed strain of S into mice and mice remain alive.
Step 4: He mixed living R strain with heat killed S strain and then inject into mice. As a result the mice died.
Conclusion: It was found that genetic material from heat killed S stain were transferred to living R (non-virulent) strain, as a result R become virulent and cause the death of mice.
When the bread and butter is in mouth, mechanical digestion starts. The size of the food gets reduced and it mixes with saliva for easy swallowing. The salivary amylase in saliva begins the digestion of starch in the bread. This is the start of chemical digestion. When the undigested bread and butter reached the stomach, lower esophageal sphincter relaxes and allow the chewed food to enter. The gastric secretions containing HCl, acts on the undigested food to produce chime. HCl kill the microorganism on the food and also denatures the protein and later attacked by digestive enzyme pepsin. Pepsin breakdown protein in the bread, butter . Later on gastric lipase begins to digest fat present in butter. Digestion of the starch in bread does not occur in the stomach because the salivary amylase that began chemical digestion in mouth became inactive in the presence of HCl. Further the chime enters the small intestine where bile secreted by the gall bladder emulsifies the fat and break into small globule which helps in fat absorption.
Answer:
supplying oxygen to cells and tissues. providing essential nutrients to cells, such as amino acids, fatty acids, and glucose.
Explanation:
it jus makes sure that we get oxygen to our cells and tissues so we dont die.
D. <span>The stomata will close until enough water is lost.</span>
Hope this helps
Answer:
Explanation:
(in an echinoderm) each of a large number of small flexible hollow appendages protruding through the ambulacra, used either for locomotion or for collecting food and operated by hydraulic pressure within the water-vascular system.