They are held together by weak hydrogen bonds
Answer:
18 is the nuclesus, 20 is the smooth endoplasmic reticulum and 21 is the golgi apparatus and 19 is the microtubes and 17 is the vacules.
Explanation:
The answer is B. Geology has shown a thin layer of iridium (a rare mineral on earth but found on asteroids and meteors) in the rock layers between the Cretaceous and Paleogene periods. Below this layer are numerous fossils of pterosaurs and dinosaurs, but above the layer are drastically few. The aftermath of asteroid impact is believed to have smothered most vegetation from earth which dinosaurs depended on as a source of food.
The class of macromolecule a steroid belongs to is a lipid.
Answer:
Their cell walls are composed of very different biochemicals.
Explanation:
Biological classification is important to classify the organisms on the basis of their similarities and differences between them. Linnaeus is known as the father of biological classification.
Cellwall plays an important role in the maintenance of structure and function of the organisms. The composition of the cell wall of fungi, plants and prokaryotes are quite different. Plants cell wall made of cellulose, fungi has chitin in its cell wall and prokaryotes has different layers of cell wall.
Thus, the correct answer is option (D).
