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<span>The statement that is least likely to support the endosymbiotic theory is that mitochondria and chloroplasts have DNA that resembles bacterial DNA.
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<span>Answer
1. electrical signal travels toward the heart
2. signal by the nodes in the atrium</span>
3. the atria contract<span>
</span>4. signal received by the atrioventricular node
5. signal transferred to the ventricles
6. the ventricles contract
Heart has a pacemaker that will continually send a signal. The primary site of the pacemaker is at the sinoatrial node, on the top right atrium. This node will send a signal to atria (which will cause it to contract) and to the atrioventricular node.
Atrioventricular node located between atrium and ventricle. It will send the signal to the ventricle(by the bundle of his) and cause it to contract.
Answer:
Biotic factors of tundra ecosystem: migratory bird species and mammals such as caribou, foxes, bears, and small rodents.
Explanation:
Biotic component of an ecosystem are the total of all the species of living beings present in the system. It includes species of plant, animals and microbes. Since tundra ecosystem is habitat for migratory bird species and mammals such as caribou, foxes, bears, and small rodents; these living beings serve as biotic component for the system.
