The Precambrian time refers to the time 4.5 billion to 542 millions year ago. This period is characterized by having reduced atmosphere and included reduced compounds. Scientists believed that atmosphere at that time was devoid of free oxygen and CO2 was present in excess. Before the complex life evolved on the Earth, the Precambrian Earth's ocean contained dissolved carbon dioxide.
Answer:
There are several environmental factors that causes changes in the ecosystem and the population of that area such as invasive species, extreme weather, land use change, pollution and disease.
Lets take invasive species as environmental factor. Introduction of invasive species can cause a huge change in the ecosystem and affects the native population in that area. it increases the competition for food resources and decreases the survival rate of their preys.
For example: Water hyacinth (Eichhornia crassipes). It is an invasive plant species that has very bad impact of native population as well as other population, like it reduces biological diversity, oxygen loss, decreased phytoplankton productivity, eliminate plants that animals use for nesting, and alter animal communities by blocking access to the water.
Thus invasive population can affect population by reducing biodiversity, water shortages, decreasing availability and quality of key natural resources, disturb the food chain and can cause natural calamities.
Invasive species affect the resources that native species are using and that decreases the carrying capacity of the native population as it disturbs the whole food chain.
It would be nitrogen, oxygen, and carbon dioxide (:
x
The respiratory system works directly with the circulatory system to provide oxygen to the body. Oxygen taken in from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.
