<u>ANSWER:</u>
The correct order is- Zygote, Blastula, Gastrula, Fetus.
<u>EXPLANATION:</u>
- The embryo develops from the zygote which is formed when the gametes fuse in the process of "fertilization".
- The zygote undergoes cell division to form blastula which is a "ball of cells".
- Gastrula leads to the rearrangement of cells of the blastula into three layers that differentiate into different systems of organ.
- The last stage is the fetus which then develops into a baby.
Answer:
paracrine signaling.
Explanation:
Chemical signaling between cells is one of the most important ways that activities of tissues and organs are coordinated. The nervous system is the other major coordinating system in animals, but even here chemical signaling is used between adjacent neurons. The mechanisms involved are described as either being paracrine, autocrine, intracrine, endocrine, neuroendocrine or pheromones. Paracrine signals diffuse locally and act on neighboring cells.
One: The cell is able to move material in and out of the cell
Two: It helps the cell maintain necessary conditions for life
Vaccines help develop immunity by imitating an infection. This type of infection, however, does not cause illness, but it does cause the immune system to produce T-lymphocytes and antibodies. Sometimes, after getting a vaccine, the imitation infection can cause minor symptoms, such as fever. Such minor symptoms are normal and should be expected as the body builds immunity.
