Final answer:
Primates constitute a small percentage of vertebrate animals used in research typically around 1-2%, as they are utilized less frequently due to ethical considerations and the costs associated with their use in studies.
Step-by-step explanation:
Primates are a group of mammals that include species such as monkeys, apes, and humans. In the context of animal research, primates comprise a small percentage of the total number of vertebrate animals used each year. While the exact percentage can fluctuate over time and depends on various regulations and practices in different regions, historically, the percentage has been relatively low compared to other vertebrates like rodents, which are more commonly used in research. In general, primates are used in research far less frequently due to ethical considerations, costs, and the need to use them only when no other alternatives are available and when the research is expected to provide significant insights into human health or fundamental biological processes. It is important to consider that primates are often essential for certain types of biomedical and behavioral research due to their genetic, physiological, and cognitive similarities to humans.
Due to these factors, the percentage of primates used in research is on the lower end of the scale. Typically, it is well under 10%, and prevailing data suggest that the correct answer would be a) 1-2% of the total number of vertebrate animals used in research each year. Nevertheless, specific statistics should be verified with current research and reports, as ethics and legislation affecting animal research are subject to ongoing change and international variance.