A radioactive element is an element which is subject to spontaneous degeneration of its nucleus followed by the emission of alpha, beta and gamma particles. All elements with atomic numbers greater than 83 are radioactive.
The given phrases that describe radioactive elements are-
They have a consistent number of particles
- the particles are alpha, beta and gamma particles.
They have a half-life that determines their rate of decay.
Explanation for other options:
Not all elements occur in nature. Radioactive decay rates may not be constant as the decay happens when a radioactive substance emits a particle. It is not possible to predict exactly when a given atom of a substance will emit a particular particle. When the radioactive element release energy and particles, it decays.
The value because it could be worth a lot or a little
Answer:
Mitochondria- often called the powerhouses of the cell — enable eukaryotes to make more efficient use of food sources than their prokaryotic counterparts. That's because these organelles greatly expand the amount of membrane used for energy-generating electron transport chains.
Explanation:
Answer:
There are only four parts of skill related fitness in the options; they are:
Speed
Agility
Balance
Coordination
Explanation:
Physical fitness refers to the ability to perform physical activities well without fatigue. In other words, being physically fit refers to a state of general wellbeing. Physical fitness can either be health-related or skill-related. The skill-related components are six in number viz: agility, power, balance, coordination, speed and reaction time.
However, only four of these skill-related parts of physical fitness are mentioned in the options of this question. They are:
- Speed: This refers to the ability to run a distance in a short time frame.
- Agility: This is the ability to move easily and quickly in different directions
- Balance: The ability to maintain an upright body position during training or physical activity
- Coordination: The ability to make physical senses of one's body (eye) cooperate with the limbs (hands and feets) during a physical activity.
Note that, Aerobic Endurance and Muscular strength are health-related components of fitness
Answer:
los mecanismos capaces de generar diversidad actúan para incrementar la variabilidad genética en la población que sufrió el cuello de botella
Explanation:
Un cuello de botella se refiere a una reducción drástica en el tamaño de una población (por ejemplo, debido a una catástrofe natural). Un cuello de botella es un fenómeno que está asociado a la reducción en la variación genética y fijación de ciertos alelos en la población resultante, lo cual es causado por la deriva genética, es decir, debido al muestreo al azar de los individuos que formarán la población en la siguiente generación. Paulatinamente, los mecanismos capaces de generar variabilidad genética aumentarán nuevamente la diversidad de la población que sufrió el cuello de botella. En una población de reproducción sexual, la variación genética se genera mediante cuatro procesos diferentes: 1-mutación (es decir, la aparición de nuevos alelos debido a alteraciones en la secuencia de ADN); 2-recombinación (es decir, el intercambio de información genética entre cromátidas no hermanas durante la meiosis); 3-segregación independiente de cromosomas durante la meiosis (capaz de producir nuevas combinaciones de alelos) y 4-fertilización al azar (lo cual también incrementa el número de combinaciones entre gametos que darán lugar a un nuevo individuo).
