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.

What is meant by carbonaceous material?

 Carbonaceous material is a term used to describe any material that is primarily composed of carbon. This can include a wide range of materials, such as coal, oil, natural gas, and organic materials like wood, paper, and food waste.

Carbonaceous materials are commonly used as fuel sources, as they can be burned to release energy in the form of heat. They are also an important source of raw materials for the production of a variety of products, such as plastics, chemicals, and pharmaceuticals.

In addition to their practical uses, carbonaceous materials are also important in a number of scientific and environmental contexts. For example, the study of carbonaceous materials can help scientists understand the Earth's climate and the role of carbon in the environment. The decomposition of carbonaceous materials can also produce greenhouse gases, such as carbon dioxide and methane, which contribute to climate change. As a result, the management and use of carbonaceous materials has significant implications for both human society and the environment.