Changes in the trilobite exoskeleton can be attributed to a. changing environments c. inter-species mating b. competition for survival d. both a and b select the best answer from the choices provided a b c d

What is difference between an epidemic and a pandemic? a) an epidemic is a disease; a pandemic is a treatment.b) an epidemic is restricted to a local region; a pandemic is global.c) an epidemic has low mortality; a pandemic has higher mortality.d) an epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection.