There are two types of alveolar cells. The type I alveolar cells which lines the alveoli and much more abundant than type II alveolar cells. Then the type II alveolar cells lesser in number but functions differently than type I alveolar cells. Type II alveolar cells secrete surfactant (composed of lecitin and sphingomyelin) for the lungs. Surfactant reduces the surface tension inside the alveoli, preventing alveolar consolidation. This is important as babies with dysfunctional type II alveolar cells (usually preterm babies less than 32 weeks age of gestation) will have respiratory distress syndrome in the absence of surfactant.
Answer:
Option D, to inform readers of the reasons why the Grimms collected their tales.
Explanation:
Edgeunity.
Answer:
recombination and independent segregation of chromosomes during meiosis
Explanation:
Recombination and independent segregation of chromosomes represent the two most important meiotic mechanisms by which sisters from the same parents can inherit different gene variants and therefore look very different from each other:
1- Independent assortment (segregation) of chromosomes: during meiosis, homologous chromosomes are randomly distributed in daughter cells (which will give rise to the gametes), and therefore separate independently of each other. It is for that reason that gametes have unique combinations of chromosomes, which increases genetic variation.
2- Recombination, also known as crossing over, refers to the exchange of chromosome segments between non-sister chromatids during meiosis. This mechanism is well-known to produce new gene variants (alleles) in the daughter cells. In consequence, recombination also increases the genetic variation of the resulting gametes that will produce offspring (in this case, different sisters).
The cell uses information from mRNA to produce protein
Explanation: