3. Which of the following are adaptations for flight in birds? 1. large heart 2. light-weight bones 3. air sacs a. 1 only
b. 1 and 2
c. 2 only
d. 1, 2, and 3

b would be the right answer

explanation:

on disadvantage of hydroelectric power is the cost. another disadvantage of using hydroelectric power is finding a water source powerful enough to harvest hydroelectric power.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.