Like Y-DNA STRs, autosomal STRs are counts of repeated genetic code. As autosomal DNA recombines each generation, the number of markers shared with a specific ancestor is reduced by half each generation.
Heroin acts as a lipid soluble âprodrugâ within the brain, meaning that heroin itself is inactive but it is metabolized into an active form within the body. After crossing the blood-brain barrier, heroin is metabolized into morphine, which actively binds to opiate receptors in the brain producing the high.
In other words, they change how the brain works. Marijuana contains more than 400 chemicals, including THC (delta-9-tetrahydrocannabinol). Since THC is the main active chemical in marijuana, the amount of THC in marijuana determines its potency, or strength, and therefore its effects.