<h3>
NEUTRONS AND PROTONS</h3>
The nucleus is a collection of particles called protons, which are positively charged, and neutrons, which are electrically neutral. Protons and neutrons are in turn made up of particles called quarks. The chemical element of an atom is determined by the number of protons, or the atomic number, Z, of the nucleus.
Answer
The correct option is B.
Explanation
Ecological succession of any species is composed of following stages:
A. Migration
The movement of species from one place to another location for the purpose of setting permanently o temporary is known as migration
. Forexample
Siberian crane (<em>Leucogeranus leucogeranus</em>) that live in the arctic tundra of eastern and western Russia. The eastern population of birds migrate to china while western population of these birds migrate to Iran, India and Nepal during winter season.
B. Ecesis
The complete establishment of species in new habitat that was completely barren or left barren due to some catastrophe is known as Ecesion. This process is dependent upon the climatic, edaphic and biotic factors. The success of plant depend upon some of the adaptations to withstand the unfavorable conditions which includes both biotic and abiotic conditions.
Forexample
The process of succession in xerosphere start on barren area from pioneer stage covered by crustose lichen, then foliose lichen followed by moss stage, herbaceous stage and a last by shrub stage.
C. Nudation
The initiation of new species by major environmental disturbance such as volcano eruption is known as Nudation.
D. Reaction
It represents the effect of established species on the habitat. Forexample plants alter habitat condition as they grow. They extract raw materials from the environment in large amounts and return metabolic wastes. The waste accumulates in large amounts and differ from the original raw materials, thus altering the environment.
E. Competition
The phenomenon which involves struggle for existence between two or more individuals growing in same area, that make excessive demand that are similar in nature on the soil is known as competition.
Such struggle may be in between same species or different species. The competition may be interspecific or intraspecific. Because of completion the weak individuals are eliminated as strong ones are retained.
Answer:
NO. Mitosis involves one set of nuclear division and results in two nuclei that are exactly the same as the original. On the other hand, meiosis involves two sets of nuclear divisions.
Explanation:
Mitosis is a type of cell division normally occurring at the sites of growth and development of new tissues and also at sites of repair. It also occurs during asexual reproduction of organisms. Each mitotic cell division is a process that follows distinct phases.
Each mitotic division results in the formation of two daughter cells which are genetically identical to the parent cell, that is they have the same number and type of chromosomes as the parent cell.
During telophase, a nucleolus develops in the nucleus of each daughter cell. The cytoplasm divides in the process called cytokinesis. An invagination develops and finally splits the cell into two daughter cell each with its own nucleus and cytoplasm.
