Speciation is b. the process by which new species are formed. They are often caused by the isolation of certain organisms in terms of environment or geographical area. This is part of the evolutionary changes that various species undergo to brought about by natural selection.
Various reasons why five trained individuals might come up with different readings are - while carrying out an experiment, the accuracy with which each individual perform an experiment varies. The readings in different instruments used while performing an experiment also differs.
There is certain percentage of error that occurs while carrying out an experiment by each of the individual. Physical conditions such as temperature, pressure changes from one place to another where the experiments are being carried out.
It's because the main photosynthesis component (Chlorophyll) mostly absorbs red and blue portions. It reflects the green portions which is why most plants are green