The scientist who published 'On the Origin of Species' is:
A. Jean-Baptiste Lamarck
B. Charles Darwin
C. Alfred Wallace
D. Gregor Mendel
Answer: Option B
Solution (By JKSSB Mock Tests)
Charles Darwin's 1859 book 'On the Origin of Species by Means of Natural Selection' laid out the theory of evolution by natural selection. Mendel's work on heredity was published later, Wallace independently conceived natural selection but Darwin's book detailed the evidence comprehensively. Lamarck proposed earlier theories.
Explanation:
Oxytocin, produced in the hypothalamus and released from the posterior pituitary, triggers the milk let-down reflex by causing myoepithelial cells around alveoli to contract upon suckling. Prolactin stimulates milk synthesis. Estrogen and progesterone are involved in breast development during pregnancy but not the immediate ejection reflex.
Explanation:
CFCs, used in refrigerants and aerosol propellants, release chlorine atoms when exposed to UV radiation in the stratosphere. A single chlorine atom can destroy thousands of ozone (O₃) molecules. This led to the formation of the 'ozone hole' over Antarctica. The Montreal Protocol (1987) successfully phased out CFCs, allowing the ozone layer to slowly recover.
Explanation:
Blood group O lacks A and B antigens on red cells but contains both anti-A and anti-B antibodies in plasma. This makes it the universal donor for packed red cells but dangerous plasma donor. Group AB has no antibodies. So, the presence of both antibodies is correct.
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