D makes the hormones cause by nervous systems
Answer:
a) Toxic (gases)
d) Bacterial
Explanation:
Septic tanks are underground structures usually built with concrete or plastic in which wastewater is treated. These tanks are generally used in rural areas and are located near bathrooms and laundry rooms.
If a septic tank is working correctly, it should produce any unpleasing smell. However, when an individual perceives a certain strong bad smell it could be due to the presence of gases (low levels of hydrogen sulfide and high levels of carbon dioxide, and methane) and anaerobic microorganisms such as sulfur bacteria which also produce methane and, therefore, strong smell.
It all depends of what kind of bad smell is the person perceiving. For example, the smell of "rotten egg" is usually due to microbial pollution and gases. Although these gases are not toxic in low levels, they could become highly toxic. It is extremely important to pay attention to smell and give the appropriate mainteinance.
The human activities in addition to natural factors that can alter the terrestrial ecosystem is deforestation.
<h3>The effects of deforestation on food web</h3>
Deforestation is a the clearing of trees in a large area of land which can be purposeful or by nature.
Human activities that leads to clearing of trees include the following:
- dam construction and infrastructure development.
One of the negative effects of deforestation on food web is the reduction in food availablity. This is so because of the loss of biodiversity that are source of food to man.
The human activities in addition to natural factors that can alter the terrestrial ecosystem is deforestation.
Learn more about deforestation here:
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