Answer: No, mRNA ( messenger RNA) model does not closely resemble the DNA strand from which it is transcribed.
This is because mRNA strand is complementary to the strand of DNA template that is used in its synthesis during the process called transcription. The polarity of DNA template is 3' to 5' whereas that of mRNA transcribed is 5' to 3' that is both the strands have antiparallel polarity.
This is the reason template DNA is referred antisense. mRNA strand more closely resembles the sense strand ( which is complementary strand of DNA template in a double helix).
The controlled experiments are performed by the scientists, when they want to study the changes in the sample on changing a single variable. So, the correct answer is option (b).
In case, all variables are kept same, no changes would be observed in the experiment sample. A controlled experiment can be performed on living thing as well as non living. But, controlled experiment cannot be performed on the things which are influenced by a lot of variables, as they cannot create realistic results. So, the option (a), (c), and (d) are incorrect.
A.
Endangered species is closer to extinction
Threatened ones are closer to becoming endangered
the answer is 1 I think Bc you need to ask yourself a lot of questions if the test went wrong
