Cells without are membrane-bound nucleus and membrane system in the cytoplasm are?

a. plant cells
b. eukaryotic cells
c. animal cells
d. prokaryotic cells

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Which kingdom includes some organisms that have no nucleus and can live in an environment with an extremely high salt content

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.