Human activity can affect the river ecosystems because first of all humans take the water and use it for themselves, they also pollute it, disturb the ecosystems and kill fish or oysters etc. in the ecosystems.
Answer: True
Succession is the phenomena in which changes in the biotic and abiotic factors of the environment leads to change in the ecosystem. A succession is a process in which a biological community is replaced by another biological community until a mature ecosystem is formed this process is influence by environmental factors. Primary succession is the primitive environment where no biotic community previously existed it is followed by secondary and subsequent succession were life forms develop and form an ecosystem. Some of the environmental factors are:
Topographical : These are the change in the region or habitat were succession occurs. Landslides, volcanic eruption, glacier melting etc. are the examples , as these topographical changes can bring reformation of the landscape. The disturbance caused by these topographical changes will allow the disturbance tolerant species to repopulate the habitat. This can be a transition from primary to secondary succession.
Soil : It is an abiotic factor.The growth of the plants requires suitable soil conditions. The type of soil will affect which species will inhabit the area. The soil moisture and pH greatly affect the number of plant species in an area.
Climate : It can influence the direction of succession. Climatic factors includes rain, wind etc. For example a region lacking proper rainfall the species will be tolerant to dry and drought conditions. The region with heavy rainfall, the species will be more tolerant to moisture. Wind being a climatic factor can cause wind erosion affect the soil quality. Wind can lead to heavy forest fires can therefore, wiped out community.
Answer:
An experiment imposes treatment on the subjects, but an observational study does not
Explanation:
Observational studies are research studies in which an effect, process behaviour etc. are observed, without any change. For example, observation of the possible effect of a treatment on subjects.
On the other hand, experimental studies are studies in which the treatment is included. Experimental studies are randomized, meaning that subjects that are in experiment are randomly put to a treated group or a control group.
I’m pretty sure it’s nanoscopic animal since nanospoic means extremely small and animal is another way of saying livestock so it’s nanoscopic animal or animals :) (I hope this helps you in any way)
