Answer: The correct answer is B) Native shellfish populations have dramatically decreased as they are outcompeted by the crabs, causing a decrease in biodiversity.
Explanation: Green crabs represent a serious threat to biodiversity in the ocean ecosystem because they are predators that feed with animals that are part of the biodiversity such as clams, mussels, and oysters. As the predators they are, they can dramatically change the ecosystem by affecting the living and reproduction of many species.
The following statements accurately reflect the beliefs on Earth's early history:
B. Scientists believe the early atmosphere lacked the oxygen necessary to support modern human life.
The following statements are incorrect:
A. Scientists believe that DNA may have existed before RNA - Scientists actually believe the opposite - RNA may have existed before DNA.
C. Scientists believe that microspheres nearly prevented the development of early life.
D. Scientists believe that oxygen was plentiful in the early atmosphere - again, scientists believed the opposite
Answer:
Transcription, mRNA (processing, transport, localization and stability), translation.
Explanation:
- Transcription is regulated in two levels, though chromatin regulation (methylation and acetylation) to loose or increase histone's affinity to DNA and through cis and trans elements such as promoters, enhancers, and silencers (cis) to active/deactivate and RNA polymerase and transcription factors and co-factors (trans).
- mRNA can be regulated using poly-A tails or 5'-caps to shorten or give them more time before they degrade, it could also be spliced to eliminate introns.
- In the translation stage, the regulation occurs during the initiation through a scanning procedure that ensures the 40s ribosomal subunit bind correctly to the untranslated portion of RNA
Hope this information is useful to you!
