1. There are two characteristics that all living beings have in common: they are made of cells and they do three vital functions.
2. All life on Earth depends on plants because they produce oxygen and food for other living beings.
7. The vessels are cells that run through the inside of the root, stem, branch and veins of the leaves and contain the water and other substances.
10 AND 11. The photosynthesis takes place inside the cells of the green parts of the plant, because they contain chlorophyll, which absorbs the sun´s energy.
13. Plants can react to changes in their environment. For example, most of plants produce flowers in spring and lose their leaves in autumn.
16. Sexual reproduction in plants consists of four stages: pollination, fertilisation, seed and fruit formation and germination.
17. The pollination: a grain of pollen is transported to the pistil of another flower by the wind or by an insect.
19. Seed and fruit formation: the pistil is transformed into a fruit and the fertilised ovules are transformed into a seed and are dispersed.