Ectopic focus or ectopic pacemaker happens when an excitable group of cells outside the normal sinoatrial node causes premature heartbeat. Sinoatrial node (SA node) is the pacemaker of the heart. Most people experience ectopic focus but persistent occurrence may need the client/patient to visit the doctor. If a client or patient complains of ectopic focus, it is better to consider his/her activity before visiting the clinic. Ask, for example if the client/patient had a vigorous exercise because it might be causing the irregular heartbeat, how often is he/she experiences such irregularity in his/her heartbeat (acute ectopic foci is usually non-life threatening, however, chronic type requires medical help), his/her lifestyle (he/she might be using illegal drugs, smokes and/or drinks alcohol,had too much coffee etc). Again, history taking is very vital.
The Earth's atmosphere would have little or no oxygen. A by-product of photosynthesis is oxygen. Photosynthesis is the process by which green plants use energy from the sun to make their own food in the leaves. The process uses sun light, water and carbon dioxide to yield oxygen and simple sugars. The simple sugars are stored in form of starch for future use by the plants, while oxygen is either used for cellular respiration or released to the atmosphere. The process of photosynthesis adds oxygen to the atmosphere and uses carbon dioxide from the atmosphere.