Question

the presence of a membrane - enclosed nucleus is a characteristic of
all cells
prokaryotic cells
viruses
eukaryotic cells
question 37 (1 point)
which proteobacteria class contains many enteric bacteria like e. coli and salmonella?
alpha
gamma
beta
delta

Explanation:

1. For the first question, prokaryotic cells lack a membrane - enclosed nucleus, viruses are not cells and do not have a nucleus in the cell - like sense, and not all cells have a nucleus (prokaryotes don't). Eukaryotic cells are defined by having a membrane - enclosed nucleus.
2. For the second question, many enteric bacteria such as E. coli and Salmonella belong to the Gamma class of Proteobacteria.

Answer:

1. D. eukaryotic cells
2. B. Gamma