Yes it does the chemicals in whatever you are smoking are more than likely altered from what it originally was, therefore the chemicals start to taint the blood vessels and damage them permanently.
Answer:
Our limbs, such as our arms and legs, grow basically at the same time and to the same length. ... Scientists are still unsure of how exactly human arms, legs, ears, or lungs grow in such a symmetrical way.
The p wave represents atrial contraction
