When DNA is unzipped, the bonds are broken.
O Nitrogen
O Hydrogen
O Covalent
O lonic

Explanation: Helicases are enzymes involved in unzipping of the double stranded DNA molecule at beginning of DNA replication. They do so by binding at DNA sequences called origins on DNA molecule then they break the hydrogen bonds between complementary base pairs causing the two strands of DNA molecule to unzip.

Explanation:

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.