The height is a good example of the genetic trait. This trait can be influenced by the environmental factors. For example, the child has inherited the trait of tall height from parents but the trait may not express in child and may get suppressed due to environmental factors such as poor nourishment or chronic illness.
As the yeast eats the sugar, it releases a gas called carbon dioxide. The gas fills the bottle and then fills the balloon as more gas is created. Each bit of yeast makes tiny gas bubbles and that puts millions of bubbles (holes) in our bread before it gets baked.
