Answer:
d
Explanation:
natural selection is where a organism adapts to their environment. Best one suited is D
Answer:
We have just seen that pathogens constitute a diverse set of agents. There are correspondingly diverse ranges of mechanisms by which pathogens cause disease. But the survival and success of all pathogens require that they colonize the host, reach an appropriate niche, avoid host defenses, replicate, and exit the infected host to spread to an uninfected one. In this section, we examine the common strategies that are used by many pathogens to accomplish these tasks.
Explanation:
The first step in infection is for the pathogen to colonize the host. Most parts of the human body are well-protected from the environment by a thick and fairly tough covering of skin. The protective boundaries in some other human tissues (eyes, nasal passages and respiratory tract, mouth and digestive tract, urinary tract, and female genital tract) are less robust. For example, in the lungs and small intestine where oxygen and nutrients, respectively, are absorbed from the environment, the barrier is just a single monolayer of epithelial cells.
Skin and many other barrier epithelial surfaces are usually densely populated by normal flora. Some bacterial and fungal pathogens also colonize these surfaces and attempt to outcompete the normal flora, but most of them (as well as all viruses) avoid such competition by crossing these barriers to gain access to unoccupied niches within the host.
Answer:
Physarum first grows as single-celled amoebae, but the amoebae fuse, and the organism loses its 'cellular' makeup. As the organism continues to grow, nuclei divide without cell division. The resulting bag of nuclei is called a 'coenocyte' or 'plasmodium'.
Explanation:
Answer:
A
Explanation:
P waves can travel through any form.
The phagocytotic barrier, which is a part of innate immunity best describes the above scenario.
Answer: Option C
<u>Explanation:</u>
The largest organ of the body is the skin, similarly the skin also an immune barrier to the body. If there is any damage in the skin , its pH gets compromised and there it calls in for a microbial attack.
When there is a cut in the skin and bacteria enter the body, the immune system responds. First, macrophages approach the area of the cut. Next, the macrophages surround any bacterial cells and engulf them, the Phagocytosis barrier which is the part of the innate immunity
