<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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Answer:
Water molecules are polar and form strong hydrogen bonds.
Explanation:
Properties like high surface tension and boiling point are unique to water due to water's polar molecules. This allows water to form very strong hydrogen bonds and give it some different abilities.
Answer:
Regulatory sites e.g enhancers and silencers
Explanation:
Gene expression involves the synthesis of gene products usually proteins and RNA. However, a certain product might not be needed at all or in small quantity. Gene regulation mechanism is the process that makes this happen. Gene regulation is the mechanism that acts to induce or repress the expression of a gene.
Gene regulation involves controlling the rate and manner of gene expression which is achieved through a set of regulatory proteins called transcription factors. Transcription factors bind to specific regulatory nucleotide sequences and help to turn "on or off" specific genes in the DNA.
Transcription factors can either be ACTIVATORS or REPRESSORS depending on whether they boost or inhibit gene expression. The binding sites for these regulatory proteins called TRANSCRIPTION factors are the regulatory nucleotide sequences on the DNA called enhancers and silencers.
This process requires large volumes of water to pass through absorption surfaces to get enough oxygen into their bodies using their mouths and gills. These body parts work like a pump to keep water moving over the gas absorption surfaces of the gills.
