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o-na [289]
3 years ago
12

About three billion years ago, single-celled organisms called cyanobacteria lived in Earth’s oceans. They thrived on the ocean’s

abundance of ___ , which they used during the process of photosynthesis. Much later, this process allowed organisms, such as fish, to survive by extracting dissolved ___ from ocean waters.
a. oxygen
b.carbon dioxide
c. nitrogen
Physics
2 answers:
quester [9]3 years ago
6 0

The first blank is carbon dioxide, second one is oxygen

pickupchik [31]3 years ago
3 0
I think its Oxygen. 
ancient cyanobacteria produced Earth's first oxygen-rich atmosphere, which allowed the eventual rise of eukaryotes. T<span>he chloroplasts of eukaryotic algae and plants are derived from cyanobacteria</span>
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What electric force would a stationary 3.8 C charge experience if it were far away from any other charges
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Answer:

The electric force will be  0 N

Explanation:

From the question we are told that

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Generally from Coulombs law the electric force  between two charges is mathematically represented as

         F = \frac{ k  *  q_1 q_2 }{r^2}

Here r is the distance of separation between that two charges.

  Now from the question we are told that the charge is far away from any other charge hence we can say that the distance between the charge and any other charge is  r = \infty

So

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2 years ago
A cube of metal has a mass of 11 grams and a volume of 1 cm . When fully submerged in water this metal cube hanging from an accu
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Answer:

0.098 N

Explanation:

From the question,

Spring scale reading = W-U............... Equation 1

Where W = weight of the cube, U = upthrust.

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Given: m = 11 g = 0.011 kg, g = 9.8 m/s².

W = 0.011(9.8)

W = 0.1078 N.

From Archimedes principle,

Upthrust = weight of water displaced.

U = (Density of water×volume of metal cube)×acceleration due to gravity.

U = (D×V)g

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U = 1000(9.8)(10⁻⁶)

U = 0.0098 N.

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Reading of the spring scale = 0.098 N

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