a. He drew a horizon line to show where the sky and earth appear to meet.
Pathogens are the main factor for plant disease in forest ecosystems. They can cause disruption to tree functions. Although some positives reside along with these diseases. They are necessary for justifying control measures. They are one way that institutions and scientists decide what is important to study. These diseases can be used to justify funding for research or management. Ecologically, they can be a way of determining what factors are important in determining forest structure and dynamics.
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