Answer:
Helper T cells stimulate B-cells to produce antibodies and killer T cells to destroy the non-self cells. Cytotoxic T cells on the other hand are direct attack cells. They can kill the micro organisms by creating pores on the invader's cell.
Explanation:
T lymphocyte mediated immunity of cell mediated immunity do not secrete antibodies but they help stimulate the B cells to produce them. Immature T cells are produced in bone marrow from where they migrate to thymus via blood. In the thymus maturation of T cells occur and then they migrate to lymphoid tissue and get differentiated into three types:
a. Helper T cells: As the name suggests, they help in activating other immune cells, in other terms they are the regulator of virtually all functions of immune system. Protein mediator called lymphokines are produced by these helper T cells in order to regulate the immune functions. Some examples of these lymphokines are: Interleukin-2 interleukin-3, interferon gamma. T helper cells stimulate the B-cells to produce antibodies.
b. Cytotoxic cells or killer T cells: The lymphokine interleukin-2 is responsible for the growth and proliferation of both cytotoxic T cells and suppressor T cells. With the help of receptor proteins on the surface of killer T cells, they bind to the specific antigen. After binding, they secrete a pore forming protein called perforins which create pores on the invaders cell membrane for water to enter into it thereby cell swells and finally lyse.
c. Suppressor T cells: They suppress the function of above two T cells.
The answer is the occipital lobe of the brain
Magma seeps up along plate boundaries and forms mountains.
Factor 1 creates competition and factor 2 creates genetic variation.
Explanation:
Question 1: Magma seeps up along plate boundaries and forms mountains.
When lithospheric plates move apart they create divergent plate margin where magma seeps up along the plate boundary and forms series of mountains. The mid oceanic ridge was formed this way.
- The lithosphere lies on the weak and molten asthenosphere.
- Different plate interactions produces a wide range of plate movement.
- Along a divergent margin usually, two oceanic plates are forced to move apart.
- The forces the asthenosphere to rise through seeps as magmatic bodies.
- The rising magma them crystallizes along the margins of the plate to form mountain chains like the mid-oceanic ridge.
- It is common to find young rocks at the plate margin and the older ones away from spreading centers.
Learn more:
lithosphere brainly.com/question/9582362
Question 2: Factor 1 creates competition and factor 2 creates genetic variation.
Scarcity of space leads to competition between organisms and availability of mates creates genetic variations.
- In an ecosystem with limited space, there will pressure on available resources.
- This will lead to different organism developing strategies to efficiently adapt to their environment.
- Organisms will in turn begin to compete with one another for the limited resources.
When we have a diverse number of mating options, genetic variation occurs. This suggests that we can have different gene combination as a result of the mating organisms.
A variation in the genetic pool of a place leads to better adaptable traits to survive the environment.
learn more:
Natural selection brainly.com/question/10367884
#learnwithBrainly
Answer:
7/16
Explanation:
<em>The proportion of the offspring from the cross that will have white flowers is 7/16.</em>
The presence of anthocyanin which determines purple coloration is conditioned by the C_ and P_ alleles. It means that the absence of one or both of C and P will result in white flowers.
Two plants, each with CcPp are crossed:
CcPp x CcPp
Offpring
1 CCPP - purple
2 CCPp - purple
2 CcPP - purple
4 CcPp - purple
2 Ccpp - white
1 CCpp - white
1 ccPP - white
2 ccPp - white
1 ccpp - white
Proportion of offspring with white flowers = 7/16
Proportion of offspring with purple flower = 9/16
<em>See the attached image for the Punnet's square analysis of the cross.</em>
