D. horizontal
A seismograph records up-down (vertical), north-south, and east-west. It does not record horizontal motions.
The correct answer to the assertion and reason is D. A is wrong but R is correct
<h3>What is an Assertion?</h3>
This refers to the statement that is meant to be proven by the use of a valid supporting detail.
Hence, we can see the given assertion that modern farming methods decrease the yield of production, there is a need to show a valid reason and this is not done, hence, we can conclude that option D is correct because A is wrong but R is correct.
Read more about assertions here:
brainly.com/question/25241318
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Answer: the four terrestrial planets must once have been hot enough to be molten (like a liquid)
Explanation: Terrestrial planets can be defined as any planet of the solar system or any exoplanet which is "Earth-like" in the sense that it is composed primarily of metals and rock, in contrast to a planet which is a gas giant.
Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars.
Scientist believing that the densest, heaviest materials are at the center and not evenly distributed can be due to the fact that they must once have been hot enough to be molten. In this case, density will take place, making the heavier under and the lighter on top.
Famous experiments that changed the world include:
Pavlov's experiments.
The double slit experiment.
The golden ray experiment.
Explanation:
Pavlov's experiments are the groundwork of much of the work that is done in the modern day in the field of psychology.
It is based on the concepts of classical conditioning and how stimuli and response makes our response behaviors work.
The double slit experiment is also one of the fundamental experiments that opened up the field of quantum physics.
The experiment was done to deflect and dissect beams of light through microscopic slits.
The golden ray experiment is responsible for the foundation of the structure of atom and how it was discovered.
A ray of light was made to fall on a gold foil and then its trajectory was noted as the form of the experiment.
