Abird sitting on a tree flies away as you walk by. which of the characteristics explains the bird's behavior?

In 2002, the rare earth elements mine in mountain pass, california was closed because

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

Animals that reproduce sexually either do it through external or internal fertilization. read the following statement and decide if it is true or false. birds reproduce through external reproduction which is because the female will then be able to protect the egg.