Scientists investigated the effect of daily iron-dextran injection dosage on the haemoglobin concentration in the blood of weaner piglets diagnosed with anaemia. Blood samples were taken from piglets that had received different daily doses of iron-dextran for four weeks. The results are shown in the table.
Daily iron-dextran dosage (mg/kg)Average haemoglobin concentration (g/dL)06.056.0106.0157.5209.02510.5\begin{array}{|c|c|} \hline \textbf{Daily iron-dextran dosage (mg/kg)} & \textbf{Average haemoglobin concentration (g/dL)} \\ \hline 0 & 6.0 \\ \hline 5 & 6.0 \\ \hline 10 & 6.0 \\ \hline 15 & 7.5 \\ \hline 20 & 9.0 \\ \hline 25 & 10.5 \\ \hline \end{array}Daily iron-dextran dosage (mg/kg)0510152025Average haemoglobin concentration (g/dL)6.06.06.07.59.010.5Plot a graph to show how the average haemoglobin concentration changes with daily iron-dextran dosage. Use a ruler to join the points with straight lines.
Use the graph to describe how daily iron-dextran dosage affects the average haemoglobin concentration of the piglets.
Suggest why a piglet with a higher haemoglobin concentration has a higher growth rate and more energy compared to an anaemic piglet with low haemoglobin concentration.
Scientists obtain blood samples from the jugular vein in the piglet's neck.
Suggest two reasons why scientists obtain blood samples from a vein rather than from an artery.
Suggest one reason why the scientists could not obtain a blood sample from a capillary.
Suggest why the needle used to obtain a blood sample needs to be sterile.
