What is the significance of the birds in the old man and the sea?

What is the broadest level of classification of life

Hummingbirds drink nectar from flowers, while robins eat plant seeds. what does this reduce?

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems