MCQ
De Vries gave his mutation theory on organic evolution while working on
- APisum sativum → Pea
- BDrosophila melanogaster → Fruit fly
- ✓Oenothera lamarckiana → Evening primrose
- DAlthea rosea → Holly hock
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Reason : Allergens in the environment on reaching human body stimulate mast cells in certain individuals.
Statement $I$ : Bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced.
Statement $II$ : Both bone marrow and thymus provide micro environments for the development and maturation of T-lymphocytes.
In the light of above statements, choose the most appropriate answer from the options given below :