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.
Answer:
(a) Monoecious
Explanation:
Monoecious refers to plants which have both male and female reproductive organs. Most of the plants have both male and female reproductive organs.
Dioecious describes a plant group that have distinct male and female plants. monoecious is also known as single house as male and female are found in single individual and dioecious is also known as double house as it has distinct male and female plants
Answer:
The correct option is;
Glaciers that once covered South Africa have melted and can no longer form.
Explanation:
The Karoo Supergroup that formed hundres of millions of year ago covered the most part of South Africa. The Tillite debris from melting glaciers, in Dwyka Tillite are located at the bottom layers of the Karoo Supergroup, which is an indication that millions of years ago, South Africa was under extensive glacier coverage formed during the movement of the continent past the South Pole
The eventual arrival of the continent to temperate regions away from the South Pole resulted in the melting of the glaciers from which a huge swamp was formed.
The biometrics used to determine growth in a forest are the number, variety, size, shape, and age of trees. 4. How can forests remove timber and still remain sustainable? Forests can remove timber and still be sustainable because sustainability just means that only the growth is removed.
If i'm not mistaken amino acids can be used in our body to fuel a process in which cell replication occurs and DNA is made. So to use amino acids as fuel you would have to make sure everything is in correct order and lines up correctly from the time it's released from the nucleus to a ribosome.
