A student wants to prove that amphibians appeared on earth before birds. The student should use the fossil findings as evidence to provide the most reliable information about the periods when amphibians and birds appeared on earth. Fossils would throw light on the internal body structures that bear the closest similarity to either the amphibians or the birds. The radiocarbon dating of the fossils will reveal its age. This can be used to figure out the time of divergence of the two types.
11 and 12 seem to be right :) For 13, only organisms which are homozygotic for a certain gene (aa) express a recessive phenotype.
14. This dna exchange between the homologous chromosomes is called crossing-over.
15. geneticly linked or coupled, the phenomenon is known as genetic linkage
16. and 17. also seem all right :)
The answer to the blank i think is bond im not 100% sure though..