What are two reasons why the heart needs its own blood supply

Apart of an ecosystem that can restrict the growth of a population is referred to as

Plz ! for many generations farmers in north america have been choosing to cross corn plants with large ears of corn each year this results in the new generation of plants also growing large ears of corn. what is the technique called? a. selective breeding. b. natural selection. c. mitosis. d. asexual budding.

The tubes transporting minerals and water upward are called ?