Forming Earth - Emergence of Life

How old is the universe?

• 13.5 billion years old

• 2 million years old

• 4.6 billion years old

• 3.8 billion years ago

How old is the Earth?

• 13.5 billion years old

• 2 million years old

• 4.6 billion years old

• 3.8 billion years ago

How long ago did life emerge?

• 13.5 billion years ago

• 2 million years ago

• 4.6 billion years ago

• 3.8 billion years ago

At the beginning of the universe, all elements that we have now already existed.

• True

• False

How did heavier elements form in the universe?

• they already existed

• solar winds brought them from another galaxy

• lighter elements like hydrogen and helium fused together during supernova explosions

• heat from the sun

What word describes when water is attracted to other substances?

• cohesion
• adhesion
• capillary action
• surface tension

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, air becomes trapped between the hydrogen bonds of water molecules.
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.

Which end of the water molecule has a slightly positive charge?

• the oxygen end
• the hydrogen end
• both ends are slightly positive
• neither end is positive

Water is a universal solvent because it...

• It can be found anywhere
• It freezes when it gets cold
• floats when frozen
• Dissolves most substances

Large bodies of water, such as lakes and oceans, do not quickly fluctuate in temperature. What is the reason for this phenomenon?

• Water is an acid.
• Water is a versatile solvent.
• Water has a high heat capacity.
•  Water acts as a buffer.