Select the option that best completes the following sentence. Einstein's general theory of relativity explained the observed redshift of galaxies by proposing that:light is always redshifted when it travels through spacethe empty space between galaxies is expandingan anti-gravitational force pushes galaxies apartgravitational waves cause galaxies to move around

Five jumbled up sentences (labelled 1, 2, 3, 4 and 5), related to a topic, are given below. Four of them can be put together to form a coherent paragraph. Identify the odd sentence and key in the number of that sentence as your answer.1. The detection of gravitational waves opened a new window into understanding the universe, allowing astronomers to observe phenomena that were previously invisible.2. Despite its significance, this discovery also posed questions about the sustainability of space exploration and its environmental impact on Earth.3. This breakthrough led to a deeper understanding of black holes and neutron stars, shedding light on some of the most mysterious objects in the cosmos.4. One of the most remarkable achievements in recent years has been the direct observation of gravitational waves, confirming a major prediction of Einstein's theory of relativity.5. As a result, scientists were able to provide more evidence supporting the Big Bang theory, offering insights into the early moments of the universe.

Select the option that best completes the following sentence. The discoveries of Slipher and Hubble revealed that:most galaxies are moving towards a common pointmost galaxies are getting further away from us, moving faster the further away they aremost galaxies are getting further away from us, all at about the same speedgalaxies stay in fixed positions

Einstein's theory of relativity gained a great deal of credibility by successfully predictingGroup of answer choicesThat light travels in straight linesThat light is a gasThat light comes from starsThat light "bends" around massive objects

Hubble discovered that more distant galaxies have greater redshift (greater recession velocity).Group of answer choicesTrueFalse

The spectral lines from a galaxy are shifted towards the red end of the spectrum. Which statement is true?Group of answer choicesthe galaxy is not movingthe galaxy is moving towards usthe galaxy is moving away from usthe galaxy is cooling