1.   Analysis of carbon isotopes in sections of the stalagmite can reveal what kinds of plant matter the water dripped through.

2.   A tantalizing hint that some diamonds were once plants or animals is that their ratios of carbon isotopes are similar to those found in living things.

3.   But using gas chromatography, the scientists have shown that degraded animal and milk fats have distinctive signatures related to the relative abundance of a particular carbon isotope.

4.   Depending on whether the horse had a browsing or grazing diet, the enamel contains different proportions of particular carbon isotopes.

5.   The British team said the ratios of carbon isotopes in the rock strongly point to biological activity.

6.   The device employs lasers whose light changes the electrical properties only of these two carbon isotopes, leaving all others undisturbed.

7.   The signature for this was the discovered ratio of carbon isotopes, atoms of the same element that have different numbers of neutrons in their nuclei.

8.   They were looking for changes in the concentrations of organic and inorganic carbon isotopes, an indication of the presence or absence of plant life.