The infectious diseases are considered as emerging when their occurrences have increased in the past few years and could increase in the coming time like SARS, H1N1, or HIV/Aids.
On the other hand, the re-emerging infectious disorders are those, which were once considered as the major health issues globally or in a specific nation, and then got diminished drastically, however, are again turning into the health issues for a substantial ratio of the population like tuberculosis and malaria.
The body wall<span> of a star fish is made up of a thin cuticle, an epidermis with a single layer of cells, a thick dermis composed of connective tissue and a thin coelomic myoepithelial layer, which allows the longitudinal and circular musculature.</span>
<span>The formation of the fertilization envelope (slow-block to polyspermy) requires an increase in the availability of </span>calcium ions.
Slow-block to polyspermy is also called cortical reaction. In this reaction, the sperm will be permanently blocked by cortical granules. The release of calcium ion will trigger this reaction.
A possible reason for the transition of algae from unicellularity
to multicellularity would be the evolution of multicellularity allowed algae to
develop traits that keep them close to the land and thus a source of nutrients.
The correct answer between all the choices given is the last choice. I
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