Biology
Assertion (A): All organisms, whether unicellular or multicellular, start their life from a single celled structure called the zygote.
Reason (R): Zygote is formed by the fusion of two unicellular structures (gametes) during the process of fertilization among higher plants and animals.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Tissues
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Answer
Both A and R are true and R is the correct explanation of A.
Reason — A is true as in sexual reproduction, both unicellular and multicellular organisms begin development from a single cell called the zygote.
R is true as a zygote is formed when two gametes (sperm and egg), which are unicellular structures, fuse during fertilization in higher plants and animals.
The formation of a single-celled zygote through fertilization explains why organisms start life from a single cell.
Therefore, Both A and R are true and R is the correct explanation of A is the correct option.
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Related Questions
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Reason (R): Meristems are undifferentiated as they divide and redivide and produce a large number of cells. They are not specialized for any particular function.
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Reason (R): Permanent tissues mature into fixed, specialised cells that carry out specific functions, so they no longer retain the ability to divide.
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Reason (R): Blood contains red blood cells and platelets whereas lymph contains only white blood cells.
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