It is the part of the digestive tract where approx 90% of the digestion and absorption of food occurs, the other 10% taking place in the stomach and large intestine. The main function of the small intestine is absorption of nutrients and minerals.That is, absorption of the nutrients and minerals in the food ingested, usually via the mouth, at an earlier stage in the digestive process.t is the part of the digestive tract where approx 90% of the digestion and absorption of food occurs, the other 10% taking place in the stomach and large intestine. The main function of the small intestine is absorption of nutrients and minerals.
Green seaweeds. Characteristics: Green colour from chlorophyll a and b in the same proportions as the 'higher' plants; beta-carotene (a yellow pigment); and various characteristic xanthophylls (yellowish or brownish pigments). Food reserves are starch, some fats or oils like higher plants.
These, along with the cyanobacteria (often misleadingly called blue-green algae), form the phytoplankton of aquatic ecosystems . Others, including all brown algae (Phaeophyta), most red algae (Rhodophyta), and many green algae are multicellular. The large marine forms of these phyla are usually called seaweeds. Plants are thought to have evolved from a class of freshwater green algae called the charophytes. Two particular groups of charophyte, the Coleochaetales and the Charales, resemble the earliest land plants (bryophytes) in a variety of ways, including the structure of their chloroplasts and sperm cells, and the way their cells divide during mitosis .