Final answer:
The loss of plant species and habitats will devastate animals and hinder human progress.
Step-by-step explanation:
The author's beliefs about the disappearing species, as stated in the excerpt, are that the loss of plant species and habitats will devastate animals and hinder human progress.
The author mentions that if species disappear, new sources of scientific information will be lost, vast potential biological wealth will be destroyed, and various valuable products and amenities will never be developed.
Therefore, the author emphasizes the importance of preserving plant species and habitats to protect biodiversity, potential discoveries, and future advancements.
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