Answer:
The correct option is <em>B. Crossing- over </em>
Explanation:
In biology, crossing over can be described as a phenomenon by which homologous chromosomes exchange segments during the process of meiosis.
The unexpected results came because the DNA segment between the homologous chromosomes was exchanged during meiosis. The alleles got shuffled by this process and hence showed the unexpected results.
Crossing over and independent assortment are phenomenon which occurs only during the process of meiosis. These phenomenons cannot be observed during mitosis.
Photochemical smog results from automobile pollutants reacting with ultraviolet light from the sun. <span>Nitrogen oxides released from the automobile are introduced into the atmosphere reacts with sunlight to produce singular oxygen atoms. Oxygen atoms then combine with molecular oxygen to produce ozone which is one of the components of photochemical smog.</span>
C. a toy train is the item that has characteristics similar to a scientific model.