We developed Natural Earth as a convenient resource for making custom maps. Unlike other map data intended for scientific analysis or military mapping, Natural Earth is designed to meet the needs of production cartographers using a variety of software applications. Maximum flexibility is a goal. Natural Earth Vector comes in ESRI shapefile format, the de facto standard for vector geodata.
A gizzard is a sack like organ at the back of the earthworms throat. The gizzard basically chews the earthworm's food since the worm doesn't have any teeth. The crop is a thin â¦ ner organ closer to the head. The crop stores food.
Birds swallow food and store it in their crop if necessary. Then the food passes into their glandular stomach, also called the proventriculus, which is also sometimes referred to as the true stomach. This is the secretory part of the stomach. Then the food passes into the ventriculus (also known as the muscular stomach or gizzard). The gizzard can grind the food with previously-swallowed stones and pass it back to the true stomach, and vice versa. Bird gizzards are lined with a tough layer made of the carbohydrate-protein complex koilin, to protect the muscles in the gizzard.