Here are the answers to your questions:
Question 1
A) Which activity might reduce habitat loss?
Answer: removing invasive species
Question 2
A) What effect do algae blooms have on ocean ecosystems?
Answer: decreased oxygen in the water
Question 3
A) Which of the following do researchers think is a primary factor in the decrease of North American bird populations?
Answer: Changes in farming practices such as draining wetlands and pesticide use
Question 4
A) The cones of lodgepole pine trees release their seeds when exposed to heat. Which abiotic event may benefit this plant?
Answer: fire