Answer:
10
Explanation:
Proteins are polymers of amino acids. 20 different amino acids are present in various combinations in different proteins. Humans are incapable of synthesizing some amino acids. These are called the essential amino acids as they must be provided in the diet.
Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine are the nine amino acids that are not synthesized in the body of adult humans and therefore, are categorized as essential ones. Arginine is a non-essential amino acid for adult humans but is essential for adult humans. Therefore, for an infant, more than 9 amino acids are essential ones.
Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by epithelial type II cells. The main function of the surfactant is to lower the surface tension at the ir/liquid interface within the alveoli of the lung. In babies born prematurely, pulmonary surfactant may not be present in adequate amounts due to insufficient exocytosis in type II alveolar cells.
Answer:
b. Two species that use a limited resource in the same way cannot coexist indefinitely
Explanation:
The competitive exclusion principle establishes that two or more species that share the same niche requirements, in the same habitat, and are in biological competition for the same resources, won´t be able to coexist indefinitely in the same space if the other ecological factors are constant. This is because species with identical niches have the same necessities, which means that they will compete for the same resources. If these species have the same requirements, they can not coexist. When the superior competitor occupies the inferior competitor´s fundamental niche, the first species has advantages over the second species and <em>monopolizes all the resources</em>. From that moment, the inferior species is displaced and must adapt to use other resources changing its behavior, or must migrate to another area where it can get access to its needs or get extinct.
When <em>two competing species coexist</em>, this is because of niche partitioning or niche differentiation. One of the species uses a <em>different resource, occupies another area, or uses the resources at different times during the day</em>. If there is not any differentiation between them, the dominant species displaces the weak species.
Niche specialization might produce genotypic separation. Subpopulations of a species diverge into new species.
So, <em>competitive exclusion refers to the exclusion of the inferior competitor by the superior competitor when there is not habitat differentiation, and both species can not share the same niche. </em>
Only plant cells have a cell wall
Radiation is used for X-rays, MRIS, any type of cancer killing.
Too much of radiation can be a dangerous thing... you could end up dying from a lot of exposure.
