Famine- High population means more mouths to feed
Disease- Diseases usually spread more quickly with people who live closer( as it can just move from one person to the other)
War- People like to fight for land, resources, money, etc. And having more of those things mean they are more able to support families, communities, and more.
(Hope this helps a little)
Plants need oxygen to survive , no oxygen mean the plant will diePlants do need oxygen to survive. They respire (take in oxygen, give off carbon dioxide) the same way that animals do. The difference is that during the day, plants also perform photosynthesis, in which they take in carbon dioxide and give off oxygen.Plants require oxygen for respiration to carry out their functions of water and nutrient uptake. In soil adequate oxygen is usually available, but plant roots growing in water will quickly exhaust the supply of dissolved oxygen and can be damaged or killed unless additional air is provided. A common method of supplying oxygen is to bubble air through the solution. It is not usually necessary to provide supplementary oxygen in aeroponic or continuous flow systems.Oxygen is vital ingredient in plant survival
Answer:
Rigid Structure i think...
Explanation:
Plant cells contain a cell wall which contributes to the <u>rigid</u> structure it obtains.
all d before I go this answer
