A farmer is growing cabbages in his field.

Plants need mineral ions for healthy growth.

Which part of the cabbage plant takes in mineral ions?

The farmer provides his cabbages with a nutrient solution containing nitrate ions and magnesium ions.

Describe the functions of these ions in plants and their deficiency symptoms.

A gardener is testing the effect of using different fertilisers on the growth of plants. 

The gardener decided to measure the growth by counting the number of leaves.

Suggest a better method of measuring the growth of the plants.

Give two reasons why your method is better than the gardener’s method.

A scientist investigated the effect of nitrate ion concentration on barley growth.

She placed barley seedlings in five test tubes containing different concentrations of nitrate fertiliser.

After a week, the scientist measured the length of the seedlings. 

Her results were recorded in a table.

What should the scientist have used as a control for this investigation?

Which seedling showed the largest change in length?

Explain how nitrate ions were absorbed by the seedlings.