Which statement concerning ecosystems is correct?

A) Stable ecosystems that are changed by natural disaster will slowly recover and
may again become stable if left alone for a long period of time.

B) Competition does not influence the number of organisms that live in ecosystems.

C) Climatic change is the principal cause of habitat destruction in ecosystems in the
last fifty years.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )