Answer:
Explanation:
A plastid is an organel that is found in the cells of plants, algae, and some other eukaryotic organisms. There are three kind of plastids; chloroplast, chromoplast, and leucoplast.
Plastids contain pigments which is used in photosynthesis and the colour pigments that determine the colour of plant.
The answer is d. A large asteroid or comet impacted the Eartg
Has normal (2n) amount of DNA;
Has twice (4n) the normal amount of DNA
Answer:
May be Nutritional but no sure
Answer:
They have helical thickening of lignin in their walls to prevent collapse
Explanation:
the primary function of Xylem and its conducting vessels tracheids is to provide support and tranport water and minerals in plants.
Xylem vessels have layers of dead materials in the walls called LIGNIN. Lignin is a polymer; a very strong, hard materials that stop water passage through it,because it contains dead cells,
Therefore the presence of deposit of these strong impermeable, ligified walls in its walls prevent its collapse during mass flow of water of transpiration pull.