The answer for the above question is Mutation.
Mutations are random spontaneous changes that occur suddenly in the DNA. A single mutation can have a large effect, however in may cases evolutionary changes are based on the accumulation of many mutations. The gene flow is any movement of genes from one generation to another and is an important source of mutation
Answer:
Only options a reflects the instances with valid experiment or conclusion.
Quality of any experiment depends upon two things reliability and validity. Reliability is measure of regeneration of results every time an experiment is performed under specific conditions.
Validity is measure of accuracy of results of an experiment. It can be check by two ways: internal validity (checks the design of the experiment) and external validity (checks if the conclusion is the real explanation of the phenomenon).
Now, in marine biologist experiment, he concluded the results only after one breeding season. This makes his results unreliable as it might have happened by chance.
Similarly, in cola experiment the taste was only checked by one candidate i.e. Karl. He might have problem in his taste buds. In addition, the temperature of cola can also affects its taste which is not taken care of in the experiment. Hence, it is not the valid experiment.
Similarly. Jeanette could use more plants for her experiment and Robert just followed only one instruction. He didn't perform any experiment.
The outer covering of a reptile egg, may be flexible, calcified eggshells, while there are some reptiles that has hard eggs. A snake lays a kind of reptile egg that is leathery. A reptile egg may differ from one another, depending on the species.
The best method for studying both the structure and the function of the brain would be the functional magnetic resonance imaging (fMRI).
This technique measures the blood flow to different brain regions in order to determine which areas are active in certain brain processes. An increase in the blood flow increases the amount the oxygen the area is receiving that is needed for the functioning of the nerve cells.
