Which of the following is a function of the protein called ubiquitin?
a.) it attaches to proteins that are marked for destruction in the cell.
b.) it assists in the removal of introns from a eukaryotic pre-mrna.
c.) it initiates the formation of a transcription complex.
d.) it adds the 3' and 5' caps to eukaryotic pre-mrna.

The correct answer is: a) It attaches to proteins that are marked for destruction in the cell.

Ubiquitin is a regulatory protein of eukaryotic cell with the various of function. The mechanism of its action involves the addition of ubiquitin to a substrate protein (ubiquitination). Ubiquitin regulatory roles are:

•marking thee proteins for degradation via the proteasome,  

•alter the cellular location of proteins,  

•promoting or preventing protein interactions.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.