Answer:
Los tres ejemplos en donde se pueda emplear una polea movil son: un aljibe, un multigym(aparato para realizar actividad fisica) y una perciana.
Explanation:
Las poleas moviles generan movimientos de traccion, donde se mueve una masa pesada o un objeto de gran peso, al utilizar este sistema de poleas el peso del objeto es disminuido.
Tiene un sistema de gancho, con cuerda y dos poleas( a veces una de estas poleas suele ser fija para poder generar el centro rotacional de la traccion)
Answer:
(look at explanation)
Explanation:
Cardiac muscle tissue works to keep your heart pumping through involuntary movements. This is one feature that differentiates it from skeletal muscle tissue, which you can control. It does this through specialized cells called pacemaker cells. These control the contractions of your heart.
Answer: Over 4 billion years ago
Explanation: The chemical reactions between carbon and water is said to bring about life according to scientists. These reactions builds largely upon four families of chemicals (lipids, carbohydrates, amino acids, and nucleic acids).
However, the actual time of life on Earth has varying speculations from different scientists in fields of study (such as molecular biology, chemistry, oceanography, etc).
Furthermore, microfossils within hydrothermal-vent precipitates dated from 3.77 to 4.28 billion years is presumed to inhabit the oldest record of life on Earth. Hence, which is presumed to have occurred after ocean formation 4.4billion years ago.
Thus, the actual date of the chemical reactions that brought about life is not rigid, but presumed to have occurred over 4billion years ago (according to research).
