When DNA is replicated, the two strands are first separated through ; each strand then becomes a against which two new strands are made.

Answered below

Explanation:

Deoxyribonucleic acid, DNA, replication is the process whereby DNA makes a copy of itself and it occurs during cell division.

When DNA is replicated, the two strands are first separated through unzipping at the origin of the replication fork. This is catalysed by the enzyme helicase. Helicase breaks down the hydrogen bonds which hold the complementary base pairs of DNA together.

Each strand of DNA to then becomes a template against which two new strands are made. One of the strands is called the leading strand and the other is called the lagging strand. Both are oriented in opposite directions.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

hope this