Answer:
Explanation:
It is called a double circulatory system because blood passes through the heart twice per circuit. The right pump sends deoxygenated blood to the lungs where it becomes oxygenated and returns back to the heart. The left pump sends the newly oxygenated blood around the body.
Answer:
harmful effect and no effect
Explanation:
No effect: most mutated genes destroy themselves before it gets to far
Harmful effect: an example of harmful effects would be down-syndrome (where you have 3 21-chromosomes and you are only supposed to have 2)