1. how the interaction between giraffe and acacia tree can be a predator–prey relationship
It's classified this way because the acacia tree (prey) doesn't receive anything in return, it's unidirectional where only the giraffe (predator) benefits.
what instance the giraffe–acacia tree relationship would be parasitic
The reason why it's not considered parasitism is because the tree actually has a way of defending itself by growing thorns. Parasitism is when the host has no way of protecting itself. Think of a parasitic worm living in one's intestines, eating away at all the nutrients of the host.
18.Two general types of life strategies allow species to thrive in varying types of environment: r-selected strategy and K-selected strategy. Given the following biomes, identify the life strategy that would be more successful in surviving the environmental conditions and provide an explanation supporting the answer. Taiga Tropical rain forest
For this, I want to direct you to a few links:
https://biology-forums.com/definitions/K-selected_specieshttps://biology-forums.com/definitions/R-selected_speciesEssentially, r-selected are species that produce a lot of offspring because the more you have, the more likely a few will become an adult. k-selected is when you have a few offspring, but raise them well enough that they reach adulthood.
Taiga -- In this environment, there are fewer predators per capita than that mentioned below. Think of bears who have a few cubs and the mother bear takes care of them until they're adults or old enough to fend for themselves. More likely k-selection would be beneficial here.
Tropical rainforest -- In this warm environment, there are many dangers animals need to avoid. A species is more likely to be r-selected because having a few offspring will likely die early given the circumstances.
Just my opinion.