Natrual variations i think
The seasonal movement of animals from one place to another (usually occurs in species with ability to flight and in large amount
Answer:
Circulatory system
Explanation:
From the right atrium through the tricuspid valve to the right ventricle through the pulmonary sigmoid valve to the pulmonary trunk to the right and left lungs to the capillary beds of the pulmonary veins to the left atrium to the left ventricle of the heart through the mitral valve, to the aorta through the aortic semilunar valve, to the whole body, to the systemic arteries, to the capillaries of the body tissues, to the systemic veins, to the superior cava vein and inferior cava vein, which enter the right atrium of the heart.
B. Eukaryotes only have a nucleus!
Answer: Giant pandas have been allowed to persist only at elevations higher than land that can be used for productive agriculture. However, as the agricultural value of land in current panda habitat increases under a changing climate, activities like growing crops and grazing livestock may further encroach on their habitat.
Explanation:
