<span>A trait that improves the fitness of its bearer, compared with individuals without the trait.</span>
Ecosystem is a community or group of living organisms that live in and interact with each other in a specific environment.
An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows.
The correct answer is A.
Toxins and various pollutants increase in concentration through the food chain in a process called biomagnification. This means that the organisms on the top of the food chain, like the herring gull, have many times greater concentration of toxins than the lower food chain level organisms because they prey on lower food chain level organisms. If a herring gull ears 100 herrings, it will have a 100x times greater concentration of toxins in its body than a herring.
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.
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