I believe the answer is delta.
Answer: Species/Organism
QUICK DISCLAIMER: "I previously said Populations but my answer was reported and removed Imao. Honestly, if someone gives you a wrong answer, don't blame them, blame yourself for not doing it on your own. Keep that in mind."
The Parasite harms host
The parasite must adapt to beat host's defenses <span />
Answer:
Explanation:Raymond Dasmann was the first person who used the term Biological diversity in 1968. He was a wildlife scientist and conservationist. But this term gain attraction in the scientific community in the 1980s.
So during 1980s the scientific community and activists were concerned about the extinction of biodiversity so this topic gain attraction as a research subject among the scientific community.
The issue of biodiversity was first published in 1987 in journal Conservation Biology which soon popularized the concept of biodiversity and became the main journal for publication of scientific research on biodiversity.
Therefore through publication, the term biodiversity appeared which gain attraction in the scientific community, society and in politics.