Human influence ecosystem by chopping down forests,and cars burning off greenhouse gases.Humans can effect the ecosystem in a negative way ,by pollution, waste dumping, over hunting of animals,over fishing,industrial gases,energy use and not using
Answer: The SA node
Answer choices are:
<span>A. </span>The AV node
<span>B. </span>The SA node
<span>C. </span>The purkinje fibers
<span>D. </span>The AV bundle
The SA node<span> is the heart's natural pacemaker consisting of a cluster of cells located in the upper part of the wall of the right atrium. (the right upper chamber of the heart). The electrical impulses are produced and sent out from there to regulate heartbeat. This is also called the sinus code. </span>
Answer:
C
Explanation:
When two species share a common niche, then one is bound to exclude the other. This is due to the stiff competition for resources. The species with a slight advantage in acquiring the resources will edge out the other species from the environment. This has been demonstrated by George Gauss using two Paramecium species grown in the same media in the lab. <em> P. aurelia</em> outcompetes <em>P. caudatum</em>
Professional antigen-presenting cells, such as phagocytes, are the first cells to encounter a pathogen (apcs). This means they have the ability to activate cells of the adaptive immune system.
<h3>What is meant by Pathogen?</h3>
- A pathogen is an organism that infects its host with disease, and the severity of the disease symptoms is referred to as virulence.
- Pathogens include viruses, bacteria, unicellular and multicellular eukaryotes, and a wide range of other organisms.
- The bone marrow of an average healthy adult generates 100 billion new neutrophils per day. Because there are so many neutrophils in the body at any given time, they are often the first cells to reach the site of an infection.
- Long thought to be a component of the innate immune system, complement has recently emerged as an important regulator of the adaptive immune response.
Therefore the correct option is D) can activate cells of the adaptive immune system.
To learn more about Pathogen, refer to:
brainly.com/question/1008643
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By using the equation F=ma (Force = Mass*acceleration), the answer is 15,100 N for the first one and 1.25 m/s^2 for the second.
