The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
Answer:
b. 2
Explanation:
Humans have typically 23 pairs of chromosomes. Each pair is composed of a chromosome from the mother and another from the father. A specific locus in a chromosome is composed of two alleles. An allele inherited from the mother and the other allele inherited from the father.
Answer:
The process by which plants make food through sunlight is called photosynthesis...
<span>This
type of symbiosis is commensalism. Commensalism is a relationship between two
organisms in which one benefits from the other and the other organism is not affected
in any way. From the question above, in the relationship, microscopic mites are
the commensals as they benefit from their host; humans and humans neither benefit
nor are harmed.</span>
Answer:
Explanation:Complementary base pairing is important in DNA as it allows the base pairs to be arranged in the most energetically favourable way; it is essential in forming the helical structure of DNA. It is also important in replication as it allows semiconservative replication.