Viruses smaller than the host they infect

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred

Agroup of organisms that changes over time is said to

If there is another new infectious disease somewhere in the world, what do you think canadian officials should do