Answer: (B) Pre-zygotic; post-zygotic.
Explanation:
Prezygotic isolation occurs before fertilization of eggs. It occurs between the two sex gametes and deter sexual reproduction between different species.
However, individuals are considered to be diverge on the phylogeny tree and different species, when they cannot reproduce.
Mechanisms of prezygotic isolation include habitat isolation, gamete isolation, mechanical isolation, behavioral isolation, and mating seasons.
Whereas, postzygotic isolation prevents the formation of fertile offspring. This phenomenon leads to production of an hybrid offspring from different species and this is a form of speciation in nature.
Mechanisms of postzygotic isolation include hybrid inviability, hybrid breakdown, and hybrid sterility.
It means they constantly interact with each other and with their environment and are dependent upon each other for survival.
Hope this helps you out :)
1. Moles Fe = 209.7 g/ 55.847 g/mol= 3.75
The ratio between Fe and CO is 2 : 3
Moles CO = 3.75 x 3 /2 = 5.63
<span>Mass CO = 5.63 mol x 28.01 g/mol= 157.7 g
2. </span><span />2Na + 2H2O --> 2NaOH + H2<span>atomic weight of sodium is 23 48.7/23 = 2.12 moles of sodium
2.12/2 x 24 = 25.44dm^3 hydrogen = 1.06 moles
so multiply it by Avogadro's number1.06 X 6.02x10^23 = 1.204x10^24 molecules of hydrogen
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