Matthias Jacob Schleiden was a German botanist who, with Theodor Schwann, cofounded the cell theory. In 1838 Schleiden defined the cell as the basic unit of plant structure, and a year later Schwann defined the cell as the basic unit of animal structure.
The best answer is D.
The mass number of an element is the sum of the number of protons and the number of neutrons. Protons and neutrons both weigh about one atomic mass unit or amu.
The nucleus of an atom is made up of protons and neutrons. Both these two types of particles are almost the same size. Almost all the mass of an atom (99%) is in the nucleus. Atomic mass therefore is really a measure of the size of the nucleus.
Answer:
Option B
Explanation:
Option D is incorrect, as increased photosynthesis would increase oxygen supply present, not carbon dioxide supply.
Option C is incorrect, as increased decomposition would increase carbon dioxide released and oxygen present is reduced, not increased.
Option A is unlikely as if this were the case, increased oxygen levels would enable bluegill fish to survive as well.
If the allele frequency of a gene for brown fur is increasing from 15 to 25 percent, the population of the bears is evolving.