B and C)
They often obtain most of their nutrients through the cell membrane as diffusion is able to take place passively and so at no energy loss to the organism, this can be essential for a single celled organism as they are able to produce a lot less energy due to having fewer mitochondria in comparison to multicellular organisms.
They also require few resources as single celled organisms are very small and so require only a small amount of raw resources for respiration because they have a small energy demand to meet.
Missense mutations.
Hope this helps!
The cell cycle is controlled by many cell cycle control factors, namely cyclins, cyclin-dependent kinases (Cdks) and cyclin-dependent kinase inhibitors (CKIs). Cyclins and Cdks, which are positive regulators of the cell cycle, activate cell cycle factors that are essential for the start of the next cell cycle phase.
Factors Affecting Cell Division
Nutrients. The nutrients present in the cell affect cell division. ...
Genetics. Genetic code regulates cell division. ...
Chemicals. Exposure to toxic chemicals such as pesticides and some cleaning chemicals can cause cell mutation. ...
Stress. Stress affects cell division.
Answer:
See below.
Explanation:
A star's energy comes from the combining of light elements into heavier elements in a process known as fusion, or "nuclear burning". It is generally believed that most of the elements in the universe heavier than helium are created, or synthesized, in stars when lighter nuclei fuse to make heavier nuclei. The process is called nucleosynthesis.
Our Sun is currently burning, or fusing, hydrogen to helium. This is the process that occurs during most of a star's lifetime. After the hydrogen in the star's core is exhausted, the star can burn helium to form progressively heavier elements, carbon and oxygen and so on, until iron and nickel are formed. Up to this point the process releases energy. <u>The formation of elements heavier than iron and nickel requires the input of energy. </u>Supernova explosions result when the cores of massive stars have exhausted their fuel supplies and burned everything into iron and nickel. The nuclei with mass heavier than nickel are thought to be formed during these explosions.
