Answer:
recombination and independent segregation of chromosomes during meiosis
Explanation:
Recombination and independent segregation of chromosomes represent the two most important meiotic mechanisms by which sisters from the same parents can inherit different gene variants and therefore look very different from each other:
1- Independent assortment (segregation) of chromosomes: during meiosis, homologous chromosomes are randomly distributed in daughter cells (which will give rise to the gametes), and therefore separate independently of each other. It is for that reason that gametes have unique combinations of chromosomes, which increases genetic variation.
2- Recombination, also known as crossing over, refers to the exchange of chromosome segments between non-sister chromatids during meiosis. This mechanism is well-known to produce new gene variants (alleles) in the daughter cells. In consequence, recombination also increases the genetic variation of the resulting gametes that will produce offspring (in this case, different sisters).
The elements are arranged from left to right and top to bottom in order of the increasing atomic number. The rows, are called periods.
Answer:
Explanation:
In a cross-section of an adult tree trunk, the outer layer that interacts with the environment is called periderm (Layer D). The second layer that follows the periderm is the phloem (Layer C). The next layer is the cambium, which produces phloem cells and xylem cells (Layer B). The secondary xylem follows the vascular cambium (Layer A) and finally, the medulla is located in the middle of the trunk.
The secondary xylem proceeds from the vascular cambium activity. Its cells are orientated in different ways composing the vertical/axial system and the horizontal/transversal system. The secondary xylem is essential to the tree growth in high because of its resistance and the capacity to transport water long distances. Secondary xylem functions are to transport water and minerals through its vessels and tracheids, to provide support and resistance to the plant, and to store reserve substances.
C. it should have been researched by at lease two others
The circulatory system is mainly made up of the heart and the blood vessels. It is closely related to the respiratory system which is primarily made up of the lungs. The digestive system is primarily made up of the gastrointestinal tract. This simply means your mouth, esophagus, stomach, small and large intestines, and rectum up until your anus. All the cells in the human body are kept alive by these systems working together in harmony.
The heart pumps blood throughout the whole body via the blood vessels. Blood, particularly red blood cells (RBC), carry oxygen and nutrients inside of them and release them to the other cells in the body. Oxygen comes from the lungs in the respiratory system every time we breathe in air. Nutrients come from the digestive system after food has been broken down to small components that can be utilized by the cells in the body.
