They are not so the question is irrelevant. Look at Eros (see link), for example.
Please clarify this qestion.
Asteroids larger than 1 km in diameter are known as planetesimals, while those over 100 km are considered minor planets. Asteroids larger than 1,000 km are usually classified as dwarf planets if they have enough mass for gravity to shape them into a round shape.
Scientists believe that asteroids will never form into planets because the gravitational forces are not strong enough to bring them together to form a rounded shape like planets have. Additionally, asteroids' orbits often intersect with other celestial bodies, which prevents them from accumulating mass to form a planet.
Asteroids, by definition, are much smaller than planets. That's one reason why they are mostly shaped irregular, unlike planets which are close to being round. The round shape is due to the increased mass (or weight) and only large masses tend to be round due to gravity.
Asteroids have irregular shapes due to their formation process and lack of gravitational forces to pull them into a spherical shape.
Asteroids are all different shapes and sizes.
on their size and shape
asteroids are big in the shape
Scientists study asteroids to better understand the early solar system.
Asteroids are much smaller, and have very little, if any, atmosphere. They also do not have enough gravity to bring them into a ball shape, so they remain erratic in shape.
You can consider a dwarf planet to be a special case from an asteroid - one that has achieved hydrostatic equilibrium, which basically means that it has enough gravity to force it into a round shape.
Gravity. It pulls the various parts of the object toward the center. Gravity increases with mass. Extremely massive objects, like planets and the larger asteroids, have enough gravity that the object must assume a roughly spherical shape.