<span>overall, around twenty million teenagers contract an STI (sexually transmitted infection) each year. </span>(The half of them are from U.S.)<span>
A sexually transmitted infection (STI) is an infection that is transmitted between partners during different forms of sexual intercourse. This infection can lead to an infectious disease, formerly called venereal disease (the name comes from Venus, goddess of love)All sexual practices that involve mutual genital or oro-genital contact with another person, or genital fluids, are considered to carry a risk of transmitting an STI. Each STI has a different risk and severity.
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Your answer is exotic animal trade
Hope I helped: )
These species are known as invasive species.
hope this helped
The enzyme needed is topoisomerase.
Topoisomerases are enzymes whose function is to regulate the unwinding of the DNA double helix. They ensure there is no overwinding or underwinding of the helix.
During the replication and transcription of DNA, the double helix becomes overwound ahead of the replication fork. If left to go on, the tension created would eventually hinder the ability of DNA and RNA polymerase enzymes to continue down the strand of DNA.
Topoimerases I and II enzymes correct this, ensuring the polymerase enzymes do their work smoothly.