Scientific name: genus: syringa
Scientific name: genus: lilium
Scientific name: citrus latifolia
Limestone is a rock made up of calcium carbonate. It is formed by sediments at the bottom of the sea compressing over time into rock. The calcium carbonate in limestone comes from thousands and thousands of shells of sea creatures.
Limestone is an ingredient of mortar, cement and toothpaste. The stone itself can be carved into statues or cut into blocks to make buildings out of.
A limousine, also spelt limosine or just limo for short, is a luxury car. Limousines are usually very long, and can seat a lot of people.
Private individuals don't generally own limousines, you generally hire one when you need it and have a professional chauffeur drive it for you. People often hire limousines at weddings.
A line is something thin that only goes in one direction (or one dimension), and has no corners. The sides of other shapes are drawn with lines. The picture is of lines painted on the floor of a railway station.