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.
Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as peanuts or bee stings.
Answer:
Homologous structures can be described structures which originate in different organisms from a common ancestor and may or may not have the same functions.
Zeuglodons can be described as ancient whales and Orca is a common whale today known as the killer whale.
<u><em>Scientific studies show that Zeuglodans and Orca have many structures in common such as:</em></u>
- <u><em>Having teeth with two roots</em></u>
- <u><em>The presence of nostrils</em></u>
- <u><em>Pelvis and internal femur bones</em></u>
The nucleus controls what happens within the cell
I believe it is “animals and plants caanot directly use all the nitrogen found in our atmosphere”
