Since the expansion of international trade, dutch elm disease and chestnut blight have nearly killed off the dutch elm and chestnut trees in america. one might infer that these diseases were the result of

introduced species
competition for space
poor tree husbandry
lack of pollinators

The most appropriate answer would be introduced species.

Introduced or invasive species refers to the organism which is not native to that ecosystem or place and can cause harm to the environment, the economy as well as human health.

So, the expansion of international trade might result in the introduction of Dutch elm disease-causing Ascomycota fungi in America.

Another example may include the introduction of water hyacinth in India.

a. seed plant structure. 1. the three main plant organs are roots, stems, and leaves. a fourth kind of tissue, meristematic tissue, is responsible for plant growth. meristematic tissue is the only plant tissue that produces new cells by mitosis. plants can lose water out of their leaves as they exchange gases with the air

explanation: