Motor neuron disease includes loss of motor neurons in the anterior horns of the spinal cord and motor nuclei of the lower brain stem.
Answer:
Refraction is the change in direction of waves that occurs when waves travel from one medium to another. Refraction is always accompanied by a wavelength and speed change. Diffraction is the bending of waves around obstacles and openings.
Food chains model energy flow through an ecosystem. Producers pump energy into an ecosystem from an environmental source, and this energy is then passed from one organism to the next.
Answer:
The correct answer is option 3. a nucleus.
Explanation:
The first genetic material present in the early organisms were RNA which was present in the microscopic organisms back then 3.5 billion years ago which means it is normal to have RNA in such microfossils chemical analysis.
Since, the nucleus was not present in early life forms of prokaryotes like bacteria. so, it is unusual to find nucleus in the fossils of stromatolite rocks.
Thus, option III is the correct answer.
Wind because its not mechanically eroding them..
