Answer:
Explanation: What is the universe made of?
Astronomers face an embarrassing conundrum: they don’t know what 95% of the universe is made of. Atoms, which form everything we see around us, only account for a measly 5%. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy. The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together. Unveiled in 1998, the latter is pushing the universe’s expansion to ever greater speeds. Astronomers are closing in on the true identities of these unseen interlopers.
2 How did life begin?
Four billion years ago, something started stirring in the primordial soup. A few simple chemicals got together and made biology – the first molecules capable of replicating themselves appeared. We humans are linked by evolution to those early biological molecules. But how did the basic chemicals present on early Earth spontaneously arrange themselves into something resembling life? How did we get DNA? What did the first cells look like? More than half a century after the chemist Stanley Miller proposed his “primordial soup” theory, we still can’t agree about what happened. Some say life began in hot pools near volcanoes, others that it was kick-started by meteorites hitting the sea.
3 Are we alone in the universe?
science 3
Perhaps not. Astronomers have been scouring the universe for places where water worlds might have given rise to life, from Europa and Mars in our solar system to planets many light years away. Radio telescopes have been eavesdropping on the heavens and in 1977 a signal bearing the potential hallmarks of an alien message was heard. Astronomers are now able to scan the atmospheres of alien worlds for oxygen and water. The next few decades will be an exciting time to be an alien hunter with up to 60bn potentially habitable planets in our Milky Way alone.
Answer:
CFC’s illustrate that technical advances can be a “double-edged” sword as CFC's were made for the advantages but soon or later it came as a disadvantage for environment.
CFC's was discovered with many advantages such as they are stable, non-corrosive, and replacement of harmful ammonia used in refrigerators and air conditioning systems. But soon it is also discovered that CFC's are destroying the upper atmosphere layer called ozone, which is a very big disadvantage for us. CFCs are major contributor to global warming after carbon dioxide.
Hence, it proves that CFC’s shows how technological advancement can be “double-edged” sword.
Answer
Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.
Answer:
Solar energy causes evaporation; uneven heating of the Earth causes air masses to move; Coriolis forces help storms to take shape; and gravity makes rivers flow downhill. Another relevant factor is the high heat capacity (or specific heat) of water.
Explanation:
hoped this helped;)
Efficiency is defined as the measure of the amount of work or energy is conserved in a certain process. At all times, in every process, work or energy is always lost or wasted due to certain interference. Not all work given is converted to useful work or energy. Thus , efficiency is calculated by dividing the energy or work output to the energy or work input then the value is multiplied by 100 to express efficiency as percentage.
Efficiency = work output / work input Efficiency = (1540 J / 1600 J) x 100= 96.25%
Thus, the answer is B.
