The correct answer is - marine organisms.
Both, the oil and the natural gas are formed on the basis of dead marine organisms. When the marine organisms were dying, they were falling in depths and onto the sea/ocean floor. The sea floor is covered with very soft sediments, and if they were not eaten by scavengers, or they have been covered with another layer of sediments, they have been relatively well preserved. As they were decomposing, the isolation, temperature, and pressure, managed to transform the dead remains of the marine organisms into oily sticky liquid that over time gained the characteristics that we see now in the oil and the natural gas.
Answer:
A secondary pollutant
Explanation:
Pollutants can broadly be classified into two main categories based on their formation or synthesis. 1: Primary pollutants, 2: Secondary pollutants.
1: Primary pollutants
Primary pollutant can be considered as any environmental pollutant that is being directly emitted from a certain source like when we burn coal carbon di oxide is directly emitted into the atmosphere so CO2 is a primary pollutant.
Similarly sulfur di oxide or SO2 is also a primary pollutant that is emitted by the gas emissions of motor vehicles.
2: Secondary pollutants:
On the other hand, secondary pollutant is something that is not directly emitted on earth as an environmental pollutant but some how it is formed due to a reaction of primary pollutant.
Such as mentioned in the question that SO2 when oxidized in air in the presence of enzymes and water, it form H2SO4 or acid rain which directly falls on earth and incurs great amount of damage to not only living organisms but also non-living organisms such as marble buildings.
Therefore, acid rain is secondary pollutant. Please see picture for better understanding.
Hope it help!
Answer:
D) observation that certain tumor-suppressor genes and oncogenes are involved in a sequential manner in the development of colon cancer
Explanation:
Cancer is defined as the abnormal growth of cells of the body. These cells multiply/replicate without control thereby forming a lump or tumor.
Cancer growth has 5 stages and they go though different multi level steps.Different finding backs this up and it includes observation about certain tumor-suppressor genes and oncogenes being involved in a sequential manner in the development of colon cancer.
C they can infect a host and cause disease
Edge 2020