science

2. - responsible for bood clotting.
4. - responsible for transporting blood, oxygen, nutrients, and waste products throughout the body.
6. - basic building block of DNA and RNA
9. - green pigment found in the chloroplasts of plants etc.
12. - contains harmful materials like nicotine
13. - how certain alleles express traits in an organism.
14. - a brown sticky that can narrow the arteries
16. - colorless, tasteless liquid that is essential for all known forms of life.
17. - colorless gas with a strong smell
18. - thread-like structures made of DNA and proteins found in the nucleus of cells.

1. - different versions of a gene that occupy the same position on a chromosome.
2. - process by which green plants, algae, and some bacteria convert sunlight into chemical energy as glucose.
3. - Two spongy organs in the chest responsible for breathing
5. - largest artery in the body.
7. - consists of red and white blood cells, platelets, and plasma.
8. - tubes that carry air from the windpipe into the lungs
10. - responsible for breathing.
11. - movement of blood between the heart and lungs.
15. - essential for energy production in all living organisms.
17. - thicker than vein.