Combine two sentences by using the ing-forms as in the example:
Economics is a social science. It studies economy. –
– Economics is a social science studying economy.

– Economics is a science. It attempts to find economic laws.
– Economists make predictions. They form the basis of economic theories.
– There is a figure. It shows the interrelations between models, theories and
reality.
– It is a text. It speaks about economics.
– It is a book. It speaks about some interesting observations.

Economics is a science attempting to find economic laws. Economists make predictions forming the basis of economic theories. There is a figure showing the interrelations between models, theories and reality. It is a text speaking about economics. It is a book speaking about some interesting observations.