Answer:
A number of complement proteins are proteases that are themselves ... factor D has no other substrate than factor B when bound to C3b. This means that factor
Explanation:
Explanation:
In the majority of cases, the extra copy of chromosome 21 comes from the mother in the egg.
In a small percentage (less than 5%) of cases, the extra copy of chromosome 21 comes from the father through the sperm.
In the remaining cases, the error occurs after fertilization, as the embryo grows.
Answer: The open ocean zone lies beyond the continental slope and contains 65% of the water in the oceans. This zone is divided further into three subzones. The sunlit zone is where photosynthesis takes place. Plankton and jellyfish are drifters that inhabit this zone.
Explanation:
Answer:
La vida en la Tierra. Los estudios de los fósiles de rocas antiguas nos revelan que la vida probablemente comenzó hace unos 4 billones de años, cuando la Tierra era muy joven. Nadie sabe cómo comenzó la vida en nuestro planeta. La mayoría de los científicos piensa que se originó en el agua líquida
Explanation:
A. They live in the polar regions of the Northern and Southern Hemispheres.
