19 Live yeast is used in making bread. The yeast is mixed with flour, sugar and water to make dough. This is left in a covered bowl for one to two hours. During this time the yeast cells respire and produce bubbles of gas that make the dough rise. Which of the following statements describe(s) an effective way to shorten the time needed for yeast to make bread dough rise? Statement 1: Leave the bowl adjacent to a warm radiator. Statement 2: Make the dough with double the normal quantities of flour and water. Statement 3: Use finely-powdered sugar instead of granulated sugar. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer 20 Gardeners in the UK sometimes make a hot-bed to grow early crops. The hot-bed consists of a pit dug into the soil and filled with 50 cm depth of fresh animal manure and 10 cm of topsoil. It is covered with a glass cover supported on a wooden frame. Which of the following statements explain(s) why a hot-bed is effective at increasing the rate of plant growth? Statement 1: Decomposer respiration generates heat in the manure layer. Statement 2: The soil around the pit and the wooden frame acts as heat insulation. Statement 3: Temperature is a limiting factor for plant photosynthesis. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer
19 Live yeast is used in making bread. The yeast is mixed with flour, sugar and water to make dough. This is left in a covered bowl for one to two hours. During this time the yeast cells respire and produce bubbles of gas that make the dough rise. Which of the following statements describe(s) an effective way to shorten the time needed for yeast to make bread dough rise? Statement 1: Leave the bowl adjacent to a warm radiator. Statement 2: Make the dough with double the normal quantities of flour and water. Statement 3: Use finely-powdered sugar instead of granulated sugar. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer 20 Gardeners in the UK sometimes make a hot-bed to grow early crops. The hot-bed consists of a pit dug into the soil and filled with 50 cm depth of fresh animal manure and 10 cm of topsoil. It is covered with a glass cover supported on a wooden frame. Which of the following statements explain(s) why a hot-bed is effective at increasing the rate of plant growth? Statement 1: Decomposer respiration generates heat in the manure layer. Statement 2: The soil around the pit and the wooden frame acts as heat insulation. Statement 3: Temperature is a limiting factor for plant photosynthesis. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 Your answer