1. Some plant diseases are caused by bacteria or viruses. These diseases spread
rapidly through the plant, sometimes killing it. Explain how the transport
system of the plant may be involved

All viruses that spread within their host tissues (systemically) can be transmitted by grafting branches or buds from diseased plants on healthy plants. Natural grafting and transmission are possible by root grafts and with parasitic dodder (Cuscuta species). Vegetative propagation often spreads plant viruses.

Explanation:

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.