The propositions are:
a.alkylating agents
b.antimetabolites
c.topisomerase inhibitors
d.nucleoside analogs
e.<span>AZT
The right answer is A,
An alkylating agent is a compound capable of adding alkyl groups to various electronegative groups under conditions present within the cells.
Antimetabolites are an anticancer drug but act differently than the alkylating agent. (interfere with folic acid)
Topoisomerase inhibitor acts by inhibiting isomerase, used in antibiotherapy (like quinolones).
Nucleoside analogs are analogs as their name says, it does not alkylate nucleotides.
AZT (</span><span>Zidovudine) is an antiretroviral drug that inhibits reverse transcriptase.</span>
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According to scientists, many years ago their was a supercontinent called "Pangaea." As years went by, the continents slowly drifted apart which is what's today. However, from recent discovers, scientists predict that in about 250 millions years from now the continents will merge again, however this time, in a different order ("Pangaea Ultima"). So the answer to your question is D.
Hope this helps. :D
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.
#SPJ2
Answer: The observation "A" leads us to conclude that the finches populations are from two different species
Explanation:
According to the biological concept of species, <em>a set of individuals are from the same species if they are able to reproduce and leave fertile offspring</em>. This is key so one species can be successful and perpetuate through time. If they cannot leave descendants, then the species will be extinct. However, it’s possible that two individuals from different species mate and have descendants, but they cannot leave fertile offspring. When they are from different species, the offspring will be sterile and it is called a hybrid.
In the case of the South American finch, the island's finch population and mainland's finch population belong to different species because their offspring is sterile. To have different features, as different feather's color, or to have other dietary preference is not enough to say that they are different species. This is because within the same species, individuals can have variations. For example, we can different eye color and belong to the same species.
