C. their DNA is very different
<span>There are two types of stimulus that travel within our body. The two types are chemical and electrical. Electrical stimulus is the type of stimulus that travels from the motor neuron to the skeletal muscle. Electrical muscle stimulation is the elicitation of muscle contraction using electric impulses.</span>
Answer:
4. The suspected causative agent must be isolated from the diseased host and grown in pure culture
Explanation:
Robert Koch (1843-1910) was one of the most important bacteriologists of all time. Famous for discovering the tuberculosis bacillus (precisely on March 24, such as today, in 1882), he also discovered the cholera bacillus and is considered the founder of bacteriology. He worked on the isolation of infectious agents and reinfections from pure cultures, experiences from which he established the "Koch Postulates".
These postulates have been taken as a reference that describes the etiology of all the causative agents of an infectious disease, although they were originally used to describe only the tuberculosis bacillus. They are the following:
1- The agent must be present in each case of the disease and absent in the healthy.
2- The agent should not appear in other diseases.
3- The agent must be isolated in a pure culture from the lesions of the disease.
4- The agent has to cause the disease in an animal that can be inoculated
Answer:
Marine mining is a process that can be done by dredging the seabed and is used for the extraction of mineral resources from the seabed, which are non-renewable, with a negative impact on marine ecosystems.
Explanation:
The illustration shows a process of marine mining by dredging, where the resource extracted is of a mineral nature, like copper, zinc, silver and gold. Gravel used for construction can also be extracted from the sea. Mineral resources extracted from the sea are not renewable.
The process of marine mining can be harmful to the ecosystems there, so it must be a process that requires control and management from the ecological point of view.
Two possible consequences of not regulating marine mining are:
- <u><em>Destruction of the habitat of life forms present on the sea floor</em></u><em>, which endangers many species and even forces migration to more stable areas, with consequences on the food chains.
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- <em><u>Extinction of marine species that inhabit the seabed</u></em><em>. The flora and fauna of the sea floor usually have slow reproductive cycles and, in the case of fish, spawning takes place on the bottom of the sea. Mining endangers the reproductive cycles of the species, leading to induced extinction.</em>
Responsible and controlled mining activity can be useful for humans, while avoiding negative consequences on the ecosystems that exist at the seabed.
