A biologist wishes to take a useful gene found in penguins and introduce it into some bacterial cells. Her experimental procedure is given below.

Use a restriction enzyme to cut a gene out of the penguin DNA.
Use a restriction enzyme to cut open a plasmid.
Treat the plasmid with DNA ligase.
Treat the plasmid with DNA polymerase.
Introduce the plasmid into bacterial cells.

A step is missing. Where should it go in this procedure?

“Mix the desired gene and plasmid together” should go after step 5.
“Mix the desired gene and plasmid together” should go between steps 3 and 4.
“Mix the desired gene and plasmid together” should be the first step.
“Mix the desired gene and plasmid together” should go between steps 2 and 3.

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.