The correct answer should be A. spores
Ferns don't have seeds and they reproduce using spores. Cones have seeds in them and seeds fall out. Pollen enters a flower and then the flower becomes a fruit. This is sexual reproduction of plants. Since ferns don't have this, they have to reproduce with spores.
Darwin's finches are a traditional illustration of an adaptive radiation. Their ancestor came on the Galapagos Island about two million years ago. With time Darwin's finches have developed into fifteen different species separated on the basis of beak shape, body size, and feeding and song behavior.
The population of finches possesses the tendency of evolving rapidly in response to a changing environment. However, they can also get extinct in condition if the weather fluctuates too briskly between the dry and wet seasons. This would most likely take place due to the immigration of genes and mutations within the genes that are conducted on to the next generations.
Thymine and cytosine are classified as "Pyrimidines" and have one ring of carbon and nitrogen atoms for each base.
In scientific inquiry, observations can be made in many ways. This includes by using the senses, or performing an experiment.