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.
Algae are distinguished on a number of different characteristics. The most important ones are: 1  the colour of the plastids (more correctly the combination of photosynthetic pigments that are present in the plastid). 2  the presence of flagella (and if so how many, how do they insert in the cell and how do they beat).