this ones simple all the others don't use sunlight because they cant make food within themselves but plants on the other hand use direct sunlight to make their food unlike the others. ;]
The tapeworm grows and reproduces in the digestive tract.
They use radiometry and pyrometry
NASA uses the Transiting Exoplanet Survey Satelite (TESS) telescope that employes this technology
This telescope measures the brightness/luminosity of stars. When this brightness drops regularly, every more or less in the same number of years, then there is the likelihood of a planet orbiting the star. The dip in brightness of the star is directly proportional to the size of the planet and the distance between the star and the orbiting planet.