The growth of the plant can be defined as the growth in the height and width( girth) of the plant.
The plant growth in the height during the time of primary growth. During this time the growth in the height of the plant takes place.
This growth takes place in the apical parts of the plant. Then after the primary growth secondary growth takes place in the plant in which the plant grows in the bark, phloem and xylem.
The woody plants grow in two manners: the primary growth and secondary growth.
The primary growth is considered the type of growth which increases the height of the plant which involves the apical meristem present at the tip of the shoot.
When the height increases up to its maximum length, then secondary growth begins which add tissues to the side that is it increases the girth by adding bark, secondary xylem and phloem.
Apart from reminding oneself that you are prepared for the presentation. You can carry out a physical exercise like the breathing exercise by taking several deep breaths and exhaling to reduce nervousness. Also you should be mindful that the audience is there to hear you and not to judge you. In that way you can ease out tension.