Which is an example of an internal influence

In which way does nicotine cause addiction? by stimulating the brain's pleasure center by increasing blood-sugar levels by decreasing dopamine levels by reducing depression and anxiety

Why girls are tan and why they fake tan

Why do rna viruses appear to have higher rates of mutation? a) rna nucleotides are more unstable than dna nucleotides.b) replication of their genomes does not involve proofreading.c) rna viruses can incorporate a variety of nonstandard bases.d) rna viruses are more sensitive to mutagens.