Was Crocodile stronger at Marineford? Or was he holding back in Alabasta?

 During the Alabasta arc, Crocodile displayed a level of power that was initially considered overwhelming by the Straw Hat Pirates. He possessed the Logia-type Devil Fruit called the Suna Suna no Mi (Sand-Sand Fruit), which granted him the ability to control and transform into sand. He had a reputation as a Shichibukai and controlled the desert kingdom of Alabasta from the shadows. His strength was showcased through his battles with Luffy and others. At Marineford, Crocodile was present as part of the war that took place at Marine Headquarters. While he did participate in the battle, he didn't display the same level of dominance as some other powerful characters present. This has led fans to speculate that he might not have been as strong as initially portrayed in Alabasta. It's important to note that power scaling and character abilities can be subject to interpretation and development by the author. Oda often keeps details deliberately open-ended to keep the story intriguing.

In The Lord of the Rings, why did Gandalf choose to ride Shadowfax and not any other horse when he entered Minas Tirith?

 In The Lord of the Rings, Gandalf the Grey chose to ride Shadowfax, the lord of all horses, when he entered Minas Tirith for a number of reasons.

First and foremost, Shadowfax was one of the most majestic and powerful horses in Middle-earth, and Gandalf saw him as the most suitable mount for the task at hand. Shadowfax was also the fastest horse in Middle-earth, and Gandalf knew that speed would be of the essence as he rode to Minas Tirith to warn the city of the approaching armies of Sauron.

In addition, Shadowfax had a special bond with Gandalf and was loyal to him. The horse had been given to Gandalf by the Lord of Rohan, Théoden, and Gandalf saw him as a gift and a symbol of the alliance between Rohan and Gondor.

Finally, Shadowfax had a special role to play in the war against Sauron. As the lord of all horses, he was able to rally the other horses of Middle-earth to fight against the forces of darkness, and Gandalf knew that his presence would be a great asset in the final battles of the war.

Overall, Gandalf chose to ride Shadowfax when he entered Minas Tirith because he saw him as the most suitable mount for the task at hand and because he knew that Shadowfax would play a vital role in the war against Sauron.