The answer is C. large changes in allele frequencies can occur in a short time.
Genetic drift is a change in the frequency of alleles in a population as a result of random sampling of organisms and it decreases genetic variation of the population. In specific circumstances, large and rapid changes in allele frequencies can occur in a short time. The smaller the population, the more susceptible it is to genetic drift.
Answer:
Multiple Sclerosis is an inflammatory disease in which myelin sheath of nerve cells of brain and spinal cord are damaged.
Explanation:
Cause:- (Exact cause of inflammation is not known)
- But damage is caused due to attack by autoimmune cells or antibodies against myelin sheath.
Types of tissues attack:-
- Oligodendrocytes and myelin sheath is damaged and stripped away from axon and the process is known as demyelination.
- Myelin sheaths are made up of fatty tissues and help in transmission of electric impulse.
Result of immune system attack:-
- Damaged myelin sheath stop forming whIte matter of central nervous system.
- Hence disrupt coordinating communication between different brain regions.
Signs and symptoms:- vary from person to person
- Diminished eyesight.
- Disrupt motor coordination.
- Weak sensory perception.
- Fatigue and dizziness.
- Speech disorder.
- Muscle weakness and spasticity.
- Difficulty in urination and stool.
Diagnosis and treatment:-
- Diagnosis include MRI T2 findings and cerebrospinal fluid specific oligoclonal bands.
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Answer:
There is no logical answer to this question.
Explanation:
The only one that it could be is that a chicken might eat meat if offered it and that cows have been witnessed eating birds before.
Answer:
Bone marrow.
Explanation:
Hematopiesis may be defined as the formation of the blood cells by the precursor stem cells. This process occurs in the bone marrow, thymus and liver.
The red blood cells are enucleated cells with the minimum span of around 120 days. These cells are processed and destroyed in the spleen. The iron is recovered from the red blood cells and sent again into the bone marrow for the production of new blood cells.
Thus, the answer is bone marrow.