Number 1: The Circulatory System is a vast network that contains organs and vessels.
number 2: Arteries have a thick wall which helps a powerful pressure from the heart.
number 3: Without the Circulatory System the body wouldn't be unable to maintain a internal environment.
number 4: The Circulatory and Respiratory system both have gas to help a or animal live in there internal environment.
number 5: Blood vessels brings oxygen to the tissues and absorbs carbon dioxide and other waste products to clear the lungs. And with out oxygen the tissues won't absorb carbon dioxide to clear out the lungs.
number 6: D
Answer:
This article discusses a group of scientists who are studying an ecosystem. What ecosystem are the scientists studying? A the Hudson River ecosystem.
Explanation:
Ans.
Cell-to-cell communication allows signalling of essential substances between the plant cells, which are surrounded by cell walls. The molecules used by plants for long-distance signalling are known as hormones, such as auxin, ethylene, and gibberelin.
These hormones are secreted by one plant cell and received by another plant cell, where it exerts it affect. Thus, the correct answer to be fill in the blank is 'option A). hormones.'
Answer: dinosaurs and birds
Plentiful collection of f<span>ossils of early birds and their most immediate predecessors has settled the century-old controversy about the origin of birds. Birds are now safely declared to evolve from a group of dinosaurs known as maniraptoran theropods. Birds have similar shape of the bones as a variety of maniraptorans have. A host of fossils have shown also that the maniraptorans lay looked alike eggs as that of birds and they resemble the birds in the way they laid their eggs also. Those reasons prove that they are most closely related.</span><span>
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Controlled burning? I think that's right.
