Answer:
The correct answer is : they have generally increased in length.
Step-by-step explanation:
Fossil records of horses clearly showed that the early horse family was small in body size with short legs which was adapted to the wooded area at that time.
During the period of time horse family adapted to the change according the environment and habitat which was changed from wooded area to grass land. They have increased in length and size of their legs become longer during evolution.
Thus, the correct answer is : they have generally increased in length.