Answer:
4. The suspected causative agent must be isolated from the diseased host and grown in pure culture
Explanation:
Robert Koch (1843-1910) was one of the most important bacteriologists of all time. Famous for discovering the tuberculosis bacillus (precisely on March 24, such as today, in 1882), he also discovered the cholera bacillus and is considered the founder of bacteriology. He worked on the isolation of infectious agents and reinfections from pure cultures, experiences from which he established the "Koch Postulates".
These postulates have been taken as a reference that describes the etiology of all the causative agents of an infectious disease, although they were originally used to describe only the tuberculosis bacillus. They are the following:
1- The agent must be present in each case of the disease and absent in the healthy.
2- The agent should not appear in other diseases.
3- The agent must be isolated in a pure culture from the lesions of the disease.
4- The agent has to cause the disease in an animal that can be inoculated
James Watson<span> and</span>Francis Crick <span> discovered the three-dimensional structure of dna in 1953</span>
Answer:
Estrogen and progesterone are both involved in preparing the endometrium for embryo implantation. Estrogen helps to ensure conception by increasing the amount of secretory glands in the uterus. Estrogen also increases blood supply to the endometrium.
Progesterone is crucial for embryo implantation and maintenance of pregnancy. Progesterone also enlarges secretory glands that produce carbohydrates, proteins and mucin that are required for embryo nourishment before implantation. Progesterone stabilizes endometrial muscles to prevent them from contracting during pregnancy.
Explanation:
- Estrogen and progesterone are steroid hormones of the reproductive system. Estrogen helps in conception whereas progesterone maintains pregnancy.
- Estrogen is secreted during the follicular phase of the menstrual cycle that promotes the growth and maturation of follicles in the ovary.
- Estrogen also induces oestrous behavior in females.
- Secreted by the corpus luteum, progesterone is also a steroid hormone, responsible for implantation of the embryo in the uterus.
It's a summarization of useless cash spendings, sorted by date.
Answer: Alexandrium catenella is a species of dinoflagellates. Alexandrium has two flagella that enable it to swim. While one flagellum encircles the cell causing the cell to rotate and move forward, the other extends behind the cell and controls the direction.
The cell wall is composed of cellulose Theca.
Length 20 - 48 μm, width 18 - 34 μm
Yellow-green to orange-brown
Forms chains of 2, 4 or 8 cells
