The experiment must maintain internal and external validity, or the results will be useless. When designing an experiment, a researcher must follow all of the steps of the scientific method, from making sure that the hypothesis is valid and testable, to using controls and statistical tests
Answer:
The temporary release of serotonin has been found to facilitate memory formation, and the temporary release of stress hormones has been found to facilitate memory formation.
Explanation:
Both serotonin and stress hormones have been proven to ease the formation of memory. Serotonin is found in the enteric nervous system, the central nervous system, and also stored in blood platelets; while stress hormones such as cortisol and adrenalin are produced by the adrenal gland when stimulated by either the hyphotalamus or the sympathetic nervous system.
Hello!
1) A small group of birds arrives from South America.
2) Geographic isolation
3) Changes in gene pool
4) Behaviors from interbreeding
I hope it helps!
Meiosis is important for organisms since it allows for genetic variation among organisms.
<h2>Further Explanation</h2><h3>Cell division</h3>
- Cell division is the process in which cells undergo division to form other new cells.
- There are two types of cell division;
<h3>Mitosis Division </h3>
- Mitosis is a type of division in which a parent cell undergoes division to yield two daughter cells that are similar to the parent cells.
- The daughter cells have equal number of chromosomes as the parent and are identical to the parent.
- This type of cell division normally occurs in somatic cells of organisms and facilitates growth and development of organisms.
<h3>Meiosis division</h3>
- Meiosis division is a type of division that occurs in gamete cells where a parent cell divides into four daughter cells that differ from the parent cells in terms of the number of chromosomes.
- In meiosis the daughter cells have half the number of chromosomes as the parent cells.
- Meiosis occurs in the gamete cells and facilitates sexual reproduction in living organisms.
- Meiosis occurs in two phases, that is, meiosis I and meiosis II
- During the process of meiosis several processes occurs that cause genetic variation among organisms.
- These processes include, crossing over, independent assortment of genes, among others.
<h3>Crossing over </h3>
- Cross over is the process that occurs during the prophase I phase of the first stage of meiosis known as meiosis I.
- During the process of crossing over, genetic material is exchanged between homologous chromosomes which enhances the genetic variation in organisms.
Keywords: Cell division, meiosis, crossing over, genetic variation
<h3>Learn more about:</h3>
Level: High school
Subject: Biology
Chapter: Cell division
Sub-topic: Meiosis
