A team of scientists uses the Hubble Space Telescope to search for evidence of planets orbiting distant stars. Which kind of investigation are they carrying out?

A laboratory experiment involves controlled conditions where variables are manipulated to observe effects in a systematic manner. In this case, the scientists are not in a laboratory setting, nor are they manipulating any parameters; they are simply observing celestial bodies from a distance.

A controlled experiment requires a specific hypothesis and involves changing one variable while keeping others constant to observe the outcome. The research conducted with the Hubble Space Telescope does not involve such manipulation; rather, it involves passive observation of astronomical phenomena.

Constructing a model refers to the creation of a representation of a system or phenomenon to predict behaviors or outcomes based on theoretical understanding. While data from the Hubble Space Telescope could inform models of planetary systems, the act of searching for planets is fundamentally observational.