Final answer:
The Earth exerts a greater gravitational pull on objects with more mass. Among the provided options, a dog typically weighs more than a bicycle, indicating that the Earth would exert a greater gravitational pull on a dog than on a bicycle.
Step-by-step explanation:
The question asks which object the Earth will exert a greater gravitational pull on in comparison to a bicycle. The force of gravity that Earth exerts on an object is directly proportional to the object's mass. If we're to identify the object with a greater gravitational pull than that on a bicycle, we must choose the object with the greater mass.
Generally, the common weights of the listed items are as follows: a dog can weigh significantly more than a bicycle, a penny is much lighter, a basketball is lighter, and a key is also lighter. Therefore, based on common weights:
- A dog usually weighs more than a bicycle, thus Earth's gravitational pull on the dog will be greater.
- A penny, basketball, and key usually weigh less than a bicycle, meaning Earth's gravitational pull on these objects will be less.
Given these broadly accepted weights, A. A dog is the correct answer.