warm up questions pg52

1. a substance that alters chemical reactions in the body 

2. to lower the risk of heart and circulatory disease 

3. a placebo is a substance like the real drug but doesnt do anything eg sugar pill using  a placebo allows the doctor to see the differnce  the drug makes . 

4. cannabis , cocaine 

5. caffine , alcohol , nicotine 

Biology 

1. plant cells have a rigid cell wall they have a permanet vacuole and they contain choroplasts 

2. diffusion is the spreading out of particles from an area of high concentration to an area of low concentartion. 

3. a) to carry oxyegen 

   b) concave shape gives the red blood cells a large surface area for absorbing oxygen . 

4. differentiation 

5. an organ system is a group of organs working together to perform a particular function . 

6. pancreas , liver , large intestine , small intestine , salivary galnds , stomach 

1. carbon dioxide , water , sunlight , chorophll 

2. a limiting factor is something that stops photosyntheisis from happending any faster . 

3. (see guide )

4. . eg using a parafinn heater 

5. respiration 

1. where an organsim is found 

2. a quadrat is a square frame enclosing a known area . 

3. the meadian is the middle vaule in order of size 

4. transcet