uma ibhetri iphansi, kodwa isesimweni esihle, kumele sisuswe futhi inqe. akubalulekile ukwenza lokhu ekhaya, ngoba ngesikhathi senqubo nokuguquguquka evala anobuthi. (4) Kusukela ngekhulu le-16 kuya kwele-17, kwabizwa ngokuthi - "Isayensi yengqondo noma ubuchopho". Abasekeli bayo abakhulu - "Thomas, Reid, Locke njll. Industrial usesBoron has the atomic number 5 and the symbol B, and is a so-called metalloid. Boron compounds have been known for many centuries and especially used in the production of glass. At the beginning of the nineteenth century, it was recognised that boron is an essential micronutrient for plants. A deficiency of boron can lead to deformation in the vegetable growth such as hollow stems and hearts. Furthermore, the plant growth is reduced and fertility can be affected. In general, boron deficiency leads to qualitative and quantitative reduction in the production of the crop. Boron is typically available to plants as boric acid [B(OH)2] or borate [B(OH)4]-. The exact role of boron in plants is not understood, but there is evidence that it is involved in pectin cross-linking in primary cell walls, which is essential for normal growth and development of higher plants.