Microfossils are tiny remains of organisms that are usually less than one millimeter in size. They can include the remains of plants, animals, and microorganisms, such as diatoms, foraminifera, and pollen. These fossils are often found in sedimentary rocks and can provide valuable information about past environments and climate conditions. Scientists study microfossils to understand the history of life on Earth and to reconstruct ancient ecosystems. They are important in fields like paleontology and geology, helping researchers date rock layers and identify changes in biodiversity over time. Microfossils can also be used in oil exploration to locate potential oil reserves.