a chemical substance produced and released into the environment by an animal, especially a mammal or an insect, affecting the behavior or physiology of others of its species.
Answer:
they form covalent bonds
Explanation:
jeesh dude j answer the dammn question
All three are bad for the environment because all three types release CO2 into the air and have throughout their constant usage helped with creating the greenhouse effect that traps heat and causes global warming. That's why clean energy is a necessity and people are developing harnessing wind and solar power.
La respuesta correcta para esta pregunta abierta es la siguiente.
Los tres avances científicos más importantes, a través de la historia para la humanidad son los siguientes.
1.- El descubrimiento de la penicilina.
El científico Inglés Alexander Fleming fue el descubridor de la penicilina en septiembre de 1928. Este descubrimiento revolucionó la historia de la humanidad.. Antes, millones de personas morían debido a las infecciones en el cuerpo humano. La penicilina resultó ser el antibiótico más efectivo descubierto hasta el día de hoy y ha salvado millones de vidas humanas desde su descubrimiento.
2.- El descubrimiento de la electricidad.
¿Te puedes imaginar un día de tu vida sin luz?
Bueno, pues así vivió la gente toda la vida hasta el siglo XVIII, cuando comenzó a entenderse y desarrollar mejores maneras de producir electricidad. Prácticamente todos los aparatos electrodomésticos, de laboratorio, hospitales, en oficinas, escuelas y demás, funcionan con electricidad. Sin ella, nuestra vida no habría producido los avances que conocemos el día de hoy.
3.- El internet.
La revolución de este siglo.
El internet nos mantiene conectados todo el tiempo a cualquier parte del mundo. Con el internet podemos hacer miles de cosas desde nuestras computadoras y teléfonos celulares, que hasta hace 15 años eran inimaginable.
<h2>
Hey There!</h2><h2>
_____________________________________</h2><h2>
Answer:</h2><h2>
_____________________________________</h2>

the Cell Theory was give by German scientists, Schleiden and T.Shwan in 1839. It stated that,
- All organism are composed of one or more cells
- The cell is the structural and functional unit of life
- It is a de novo structure, that means it COULD arise from non living thing which was incorrect.
It was corrected by the German pathologist Rudolf Virchow in 1855. He made a convincing case, corrected and added the third point of the cell theory. It is,
- Cells can arise only by a division of pre-existing cell. It is <u>NOT</u> a de novo structure.
Cell theory brought a great evolution in the field of biology which established the function of organism is the result of activities and interaction of the cell units.
<h2>
_____________________________________</h2>

- <u>Flask 1</u>: It is observed that there are no micro-organism, this is because the meat is sealed and no micro-organism could enter through it.
- <u>Flask 2</u>: It is observed that there are micro-organism present because meat is not sealed but open.
- <u>Flask 3</u>: As the S tube is used, the micro-organism are not able to reach the meat because of the curvy path
These observations support the point that<u> cells could arise only by a division of pre-existing alive cells</u> because in Flask 1 when there were no micro-organism present so there was no organisms found so no micro-organism arised, In flask 3 the S tube was used so no micro-organism could reach the meat thus there were no organism there which could divide to reproduce. The flask 2 was open, so the micro organisms reached the meat so they divided which means Cells can only arise by a division of pre-existing cells.
<h2><u>
_____________________________________</u></h2><h2>Best Regards,</h2><h2>'Borz'</h2>