TASK DEFINITION: You are given a sentence and your task is to generate another sentence that supports the given input.
PROBLEM: Thus having four limbs is a derived feature that separates tetrapods (mammals, birds, amphibians, reptiles and some fish) from all other organisms.

SOLUTION: Birds have four limbs.

PROBLEM: The heart becomes the first working organ in the human body, pumping by rhythmically opening and squeezing shut just 17 days after conception.

SOLUTION: In humans, the heart is the first organ to form and become functional.

PROBLEM: In physics, work is defined as a force acting upon an object to cause a displacement .

SOLUTION:
In physics, work means the use of force to move an object.