I believe your answer would be:
A. Fossils.
Explanation:
Because they are the preserved remains or traces of animals, plants, and other organisms from the past. They're also important evidence for evolution because they show that life on earth was once different from life found on earth today.
Hope I helped, good luck! =)
The Americans colonies became free and independent states explanation: because they declared independence
They were brought to Australia to assist the exploration of inland Australia.
B. a specific place on a chromosome where a particular gene resides.
A locus (plural loci) in genetics is the position of a gene on a chromosome. Each chromosome carries many genes; humans' estimated 'haploid' protein coding genes are 19,000-20,000, on the 23 different chromosomes. A variant of the similar DNA sequence located at a given locus is called an allele.