Why are tomatoes red ?

Tomatoes are triggered to turn red by a chemical called ethylene. Ethylene is odorless, tasteless, and invisible to the naked (human) eye.

Explanation:

As the tomato ripens, its color starts to change from green to yellow and then eventually to red. This is due to the breakdown of chlorophyll, which in turn synthesizes a red carotenoid (another pigment group), lycopene. When ripe, the carotenoid can easily be seen as the dominant color of the tomato, red

Explanation:

in biology you'll learn more about this

thymine. in rna, thymine is replace by uracil

the circled areas are referred to   as sunspots.   the sunspots are cooler than the   surrounding area.

sunspots are temporary phenomena on the photosphere of the sun that appear visibly as dark spots compared to surrounding regions. they correspond to concentrations of magnetic field flux that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere.