mantrid

physical factors are the main cause of death for plants (not annuals etc) weather extreme winters very hot summers earth movements changes in the habitat (bog drying out with your pitcher) earthquakes etc disease humans and eventually (with tall trees anyway) they get too big and the laws of physics stops them they become too heavy and fail structurally, disease gets in and quickens their demise

in summary Plants and animals both carry out respiration but only plant carry out photosynthesis Animals obtain oxygen for respiration and get rid of carbon dioxide from respiration by breathing (lungs) Plants get rid of gasses from the leaves and into them by diffusion Note I didnt say which gasses go in and out of the leaf as that would vary according to the light levels ie at night there would be a net movement of oxygen in and carbon dioxide out. In the day the reverse, as much more oxygen is being made than being used and much more carbon dioxide being used as being made (because of photosynthesis) Some people recommend that you take plants out of the bedroom in the night as they take up oxygen, in some hospitals this is a policy! It is total nonsense of course because the amount of oxygen used by a plant is a tiny fraction of that used by a person, and you have no problem sharing a room with another person at night.

Hi I teach Biology to A level Im trying to get my head around the light reaction. I studied this during my degree along time ago and the books I used then are probably out of date. I would like to know how the hydrogen ions remain balanced across the thylakoid membrane. This level of understanding is not important for the course I teach but I have become curious. I have created an animation to help me understand using various text books but there appears to be a build up of H+ ions on the stoma side and a removal on the thylakoid side. To counteract this my animation requires I keep adding an extra ion to the thylakoid side and remove 3 H+ from the stroma side. Please take a look at the animation and tell me where Im going wrong link below http://www.iddsoftware.co.uk/Resources.php and click the light reaction picture Thank you