Which structure in the lymph vessels ensure that lymph flows in one direction

Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which statement is true of these bird species? a. they have adapted to different niches due to competition b. they have a carnivorous relationship with the tree species. c. they have adapted to different niches due to predation d. they have a symbiotic relationship with the tree species.

Asegment of dna that codes for rna and a protein is a

The function of the excretory system is to control homeostasis and