Species

The graph shows the oxygen dissociation curves of haemoglobin from two species of mammals, s and T . Which statements could explain the difference in the oxygen dissociation curves of species S and species T ? I. Species T has higher haemoglobin concentration in its red blood cells than species S. II. The haemoglobin in species T has a lower affinity for oxygen than the haemoglobin in species S. III. Species T may be living at a higher altitudes than species S.

In laboratory experiments, two species of the protist Paramecium (species 1 and 2) were grown alond and in the presence of the other species. The following graphs show growth of species 1 and species 2, both alone and when in mixed culture with the other species. Which of the following conclusions can be drawn from the graphs ?