Answer:
The Rhizaria are supergroup species of mostly unicellular eukaryotes and classified as protista. Rhizaria include species like cercozoa, foraminifera and radiolaria.
<u>Some of the attributes of Rhizaria are:</u>
- non-photosynthethic in nature, but some have a symbiotic relationship with unicellular algae.
- express only rDNA sequences so they can vary in different forms.
- do not have clear morphological characters
- they mostly includes amoebas which functions for food engulfing and help to direct movement in rhizarian protista.
<u>Contribution of Rhizaria to the ecosystem:</u>
- There are known as abundant bacterial grazers, and play very important role in microbial food webs.
- They provide a wide diversity of marine organisms.
- important contributors to oceanic carbon pools .
Hence, Rhizaria are important part of ecosystem.
Answer:
Mainly the gravitational instability in the clouds of dust (molecular clouds)
Explanation: Stars are born within molecular clouds, which are mostly made of hydrogen and lesser amounts of helium and other heavier elements. The formation of a protostar begins when gravitational instability is present in the molecular cloud, caused by regions of higher density. Eventually, the clouds of dust start to collapse to due gravity, the protostar forms. The protostar, is still an underdeveloped star, meaning it does not perform nuclear fusion in its core, but it still produces its own heat from the extreme pressure.
Answer:
the answer is D. None of the above.
After the Cretaceous–Paleogene extinction event wiped out the non-avian dinosaurs (birds being the only surviving dinosaurs) and several mammalian groups, placental and marsupial mammals diversified into many new forms and ecological niches throughout the Paleogene and Neogene, by the end of which all modern orders had appeared.