They are galaxies that are identified with the letter S and they may be the most frequent type in the Universe and they have the shape of a whirl.

This type of galaxies are very simple, and formed only by the nucleus and the halo, tend to have a flatter shape, and do not have new stars (white or blue), but are formed only by red stars with scarce gas and cosmic dust.

The most distinctive characteristic of these galaxies is that they look chaotic and undefined.

This theory suggests that the Sun, the planets, and satellites (including the moon) of the Solar System were formed from a gas cloud slowly rotating until it contracted by the gravitational force. This is the most accepted theory in the origin of the Solar System.

All of these are components of our Solar System, EXCEPT:

They are dull bodies that are capable of reflecting light and revolve around the Sun in elliptical orbits.

This term refers to rocky bodies, of different shapes and sizes that orbit around the Sun, especially in the inner Solar System.

They are solid bodies that originate from the destruction of comets or asteroids and that cross space with big velocity. One of them smashed into the Yucatán Peninsula 66 million years ago, killing some 75 percent of life on Earth, including all non-avian dinosaurs.

Their name means “hairy body” and they are low-density bodies, basically cosmic snowballs of frozen gases, rock, and dust roughly the size of a small town.

Make a quick research online, and select which of these are the correct internal structures of the Sun.

It is the Earth’s only natural satellite, a sphere composed of heavy chemical elements such as aluminum, calcium, iron, magnesium, silicon, and others.

The Moon crosses phases during its movement around the Earth. Its revolution also has an effect on Earth like the tides (wow!). The most common phases of the Moon are the following, EXCEPT:

The research into the layers’ structure of Earth is carried out mainly through the study of the seismic waves propagation, which behaves differently if they travel either in liquid or solid media. Which of these are the classification of the Earth's layers?

Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. What is true about them?

Where is Earth's heat energy most concentrated?

Which of the following best describes the location of the mantle?

The most common landscape forms are the following, EXCEPT:

Observe the next diagram and relate each letter to its corresponding part.