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2 years ago

According to scientific evidence, earth’s earliest atmosphere lacked oxygen. Over time, oxygen was added to the atmosphere.

1 answer:

4 0

B.
The cynobacteria were already there without the oxygen, so that rules out A, and a lot of prokaryotes were anaerobic, so that rules out C. Finally, Photosynthesis does not require oxygen. Instead, Oxygen is a waste product of it. Therefore, it cannot be D. So, we are only left with B
Hoped this helped :D

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19. Which of the following best describes the role of the spark from the spark plug in an automobile engine?

sergey [27]

The role of a spark plug is to supply some of the energy of activation for the combustion reaction.

Explanation:

A Spark plug is a tiny bolt of lightning in which a spark of electricity is emitted across a gap creating the ignition of the combustion chamber thereby starting the engine. By putting an engine piston in motion we can power up which produces a smooth burn of the compressed air-fuel mixture.

An electrical device that fits into the cylinder head and ignites compressed aerosol gasoline by an electric spark. They have an insulated electrode connected to a coil that ignites thereby producing sparks.
The spark plug works as a heat exchanger. They tend to pull unwanted thermal energy from the combustion chamber and heat is transferred to the engine's cooling system. Thus they supply some of the energy for the activation of engines.

4 0

3 years ago

A plastic bottle is closed outdoors on a cold day when the temperature is −15.0°C and is later brought inside where the temperat

Lana71 [14]

Answer:

Pressure = 1.14 atm

Explanation:

Hello,

This question requires us to calculate the final pressure of the bottle after thermal equilibrium.

This is a direct application of pressure law which states that in a fixed mass of gas, the pressure of a given gas is directly proportional to its temperature, provided that volume remains constant.

Mathematically, what this implies is

P = kT k = P / T

P1 / T1 = P2 / T2 = P3 / T3 =........= Pn / Tn

P1 / T1 = P2 / T2

P1 = 1.0atm

T1 = -15°C = (-15 + 273.15)K = 258.15K

P2 = ?

T2 = 21.5°C = (21.5 + 273.15)K = 294.65K

P1 / T1 = P2 / T2

P2 = (P1 × T2) / T1

P2 = (1.0 × 294.65) / 258.15

P2 = 1.14atm

The pressure of the gas after attaining equilibrium is 1.14atm

3 0

3 years ago

Upon balancing the equation what is the smallest possible integers that goes in front O₂? HBr + O₂ ➞ H₂O + Br₂ *

Leokris [45]

Answer:

Explanation:

4 HBr + O2 → 2H 20 + 2Br 2

...............

7 0

2 years ago

Read 2 more answers

In Humans, the liquid waste

Kay [80]

The answer is b (bladder)

8 0

3 years ago

Enter the atomic symbol, including mass number and atomic number, for iodine-130.

WINSTONCH [101]

Answer: The atomic symbol of the given element is $_{53}^{130}\textrm{I}$

Explanation:

The general isotopic representation of an element is given as: $_Z^A\textrm{X}$

where,

Z represents the atomic number of the element

A represents the mass number of the element

X represents the symbol of an element

For the given isotope: 130-iodine

Mass number = 130

Atomic number = 53

Hence, the atomic symbol of the given element is $_{53}^{130}\textrm{I}$

6 0

3 years ago