A red indicator solution was mixed with agar, and the resulting solid was cut into small cuboid blocks. The blocks were placed in an acid which turns the indicator yellow, and all other variables were kept constant. The dimensions of the three blocks used are shown.
block $13 \mathrm{~mm} \times 3 \mathrm{~mm} \times 3 \mathrm{~mm}$
block $2 \quad 8 \mathrm{~mm} \times 8 \mathrm{~mm} \times 8 \mathrm{~mm}$
block $3 \quad 11 \mathrm{~mm} \times 11 \mathrm{~mm} \times 11 \mathrm{~mm}$
Which row shows the correct surface area (SA) to volume (V) ratio for each block, and the time taken for the block to turn yellow?

The dimensions of three agar cylinders, X, Y and Z, are summarised in the table.

What is the correct order of surface area: volume ratio for the cylinders, from smallest to largest?

The table compares the surface area to volume ratios of five agar blocks that differ in dimensions but which all have the same volume.

The agar blocks can be used to measure the efficiency of diffusion, where efficiency is measured as the time taken for a dye to reach all parts of the block.

Which prediction can be made about the way in which size and dimensions of these blocks affect the efficiency of diffusion?

An indicator mixed with agar forms a pink colour. The pink-coloured agar becomes colourless when put in acid.

Blocks of pink-coloured agar are cut to different sizes and put in acid. All other variables are kept constant.

Which block becomes colourless most quickly?

A red indicator solution was mixed with agar and the resulting solid was cut into small cylindrical blocks. The blocks were placed in an acid which turns the indicator yellow and all other variables were kept constant. The dimensions of the blocks are shown.

The formula for calculating the surface area of a cylinder is $2 \pi r h+2 \pi r^{2}$. The formula for calculating the volume of a cylinder is $\pi r^{2} h$.

Which row shows the correct surface area (SA) to volume (V) ratio for each block and the time taken for the block to turn yellow?

Barlinka is a variety of the common grapevine, Vitis vinifera. Barlinka grapes are used for making wine and are sold as fruit. There are economic and ecological benefits from using less water to irrigate grapevine plants, while still producing a high crop yield.

The rate of flow of sap within xylem vessels from roots to leaves can be used as an estimate of the rate of transpiration. This also indicates water uptake.