Answer:
All of the above.
Explanation:
An audio-visual element is an electronic media that comprises of both sound (audio) and video (visual) used for teaching or a presentation.
The movement and audio-visual elements of these type of visual aid that capture audience attention are film, videotape, and multimedia.
Being that audio-visual possess both sound and visual components, they're able to foster and enhance deeper knowledge or understanding about a particular subject being played.
Multimedia such as films, videotape, mobile phones, computers, television etc are all audio-visual elements that has a robust graphical user interface and as such it focuses on improving on the cognitive abilities of it's audience or learner.
An audio-visual element basically captures the attention of the audience and keeps them glued, motivated and eager to learn more, as they can both see and hear the information being passed at the same time.
Answer:
The biggest disadvantage of coal is that it will one day run out with how fast the economy is using it today. It also creates carbon dioxide, which is hard to breath and also clogs up the atmosphere, making it thicker and trapping more heat. a better alternative is wind, solar, and water energy. these are clean, electronic ways to power and save our world
Explanation:
Answer:
Visible Light Absorption
Atoms and molecules contain electrons. It is often useful to think of these electrons as being attached to the atoms by springs. The electrons and their attached springs have a tendency to vibrate at specific frequencies. Similar to a tuning fork or even a musical instrument, the electrons of atoms have a natural frequency at which they tend to vibrate. When a light wave with that same natural frequency impinges upon an atom, then the electrons of that atom will be set into vibrational motion. (This is merely another example of the resonance principle introduced in Unit 11 of The Physics Classroom Tutorial.) If a light wave of a given frequency strikes a material with electrons having the same vibrational frequencies, then those electrons will absorb the energy of the light wave and transform it into vibrational motion. During its vibration, the electrons interact with neighboring atoms in such a manner as to convert its vibrational energy into thermal energy. Subsequently, the light wave with that given frequency is absorbed by the object, never again to be released in the form of light. So the selective absorption of light by a particular material occurs because the selected frequency of the light wave matches the frequency at which electrons in the atoms of that material vibrate. Since different atoms and molecules have different natural frequencies of vibration, they will selectively absorb different frequencies of visible light.
Answer:
Humans were nomads. Their wandering was mainly in search of food and shelter. When they found that certain places had an abundance of food – plant food or animals for hunting, they stayed on. They observed the plants, their growth and when these food sources diminished, they grew plants themselves, from the seeds they collected. This is how agriculture came about.
When humans stopped their nomadic ways and stayed together, it paved the way for formation of the human social structure. Hierarchies were established in due course.
Jin Dynasty which was in China and for east africa I cant find or remember anything from their the closest is the Islamic empire.
