How can each copy of DNA at the end of replication be compared? A. Each copy is identical to each other
B. Each copy is different from each other
C. They are 90% similar
D. They are 50% similar

At the end of DNA replication, each copy is identical to each other (option A).

Explanation:

The concept of DNA replication implies that, from an original molecule, two identical molecules are obtained.

DNA replication is based on a semi-conservative model, since the double strand is separated, and each strand serves as a mold for the synthesis of a new strand. At the end of the replication, two identical DNA molecules will be obtained, each consisting of an original strand and a new one.

The best evidence that the replication process results in two identical molecules is that, otherwise, an individual's genetic information could vary, which does not happen.

The other options are not correct because:

    B. The copies cannot be different.

    C and D. They are 100% identical, not partially (50 or 90%) similar.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.