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Naddika [18.5K]
4 years ago
15

A person has been exposed to a particular antigen and now experiences a repeat exposure. What stimulates a quicker immune respon

se?a) Memory T cellsb) immunityc) antibodiesd) macrophages
Physics
1 answer:
Anit [1.1K]4 years ago
7 0

Answer:

a. Memory T cells

Explanation:

Memory T cells are actually the antigen-specific T cells that remain long-term after an infection has been eliminated. These memory T cells are quickly converted into large numbers of effector T cells upon reexposure to the specific invading antigen, thus providing a rapid response to past infection that has been experienced before

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The position of a car at time t is given by the function p(t)=t2 2t−4. What is the velocity when p(t)=11? assume t≥0
AysviL [449]

The velocity when function p(t)=11 is 8 .

According to the question

The position of a car at time t  represented by function :

p(t)=t^{2} +2t-4

Now,

When  function p(t) = 11 , t will be

p(t)=t^{2} +2t-4

11 = t²+2t-4

0 = t² + 2t - 15

or

t² +2t-15 = 0

t² +(5-3)t-15 = 0

t² +5t-3t-15 = 0

t(t+5)-3(t+5) = 0

(t-3)(t+5) = 0  

t = 3 , -5  

as t cannot be -ve as given ( t≥0)

so,

t = 3

Now,

the velocity when p(t)=11

As we know velocity = \frac{position}{time}

therefore to get the value of velocity from  function p(t)

we have to differentiate the function with respect to time

\frac{d(p(t))}{dt} =\frac{d}{dt} (t^{2} +2t-4)

v(t) = 2t + 2  

where v(t) = velocity at that time

as t = 3 for  p(t)=11  

so ,

v(t) = 2t + 2  

v(t) = 2*3 + 2  

v(t) = 8

Hence, the velocity when function p(t)=11 is 8 .

To know  more about function here:

brainly.com/question/12431044

#SPJ4

4 0
2 years ago
Match each label to the boundary it describes. convergent boundary new crust forms transform boundary crust submerges into the m
Paraphin [41]

The answers would be:

CONVERGENT boundary - Crust submerges into the mantle

TRANSFORM boundary - neither forms nor submerges

DIVERGENT boundary - new crust forms

If you'd like to know more about the different boundaries, read on:

Convergent boundaries occur when two plates move TOWARDS each other. The event where crust submerges into the mantle is called <em><u>subduction</u></em> and this occurs when an oceanic plate and a continental plate collide. The oceanic plate is more dense and thinner than the continental plate, so it slides under it.

Transform boundaries occur when two plates slide against each other. They move slide side by side, so nothing is formed nor do they go under each other. Although, this type of boundaries create strong earthquakes.

Lastly, divergent boundaries occur when two plates move apart. The separation creates a way for magma to come up. New crust is formed when the magma that seeps out is cooled by its cooler surroundings. This is observed in the mid oceanic ridge.

7 0
3 years ago
Read 2 more answers
Rank the nonmetals in each set from most reactive (1) to least reactive (3). Bromine: Chlorine: Iodine:
ANEK [815]

The most reactive element of this list is Chlorine, the next most reactive is bromine, and the least reactive is iodine.

All of these three elements are group 7 elements in the periodic table. It is known that the reactivity of group 7 elements decreases down the group. The most reactive element in this group is Flourine  with reactivity decreasing down the group.

The reason for this decrease in reactivity is that as you go down the group, the distance between the positive nucleus that attracts valence electrons increases, decreasing the electrostatic attraction between the nucleus and the outer electrons. The other reason is that the electrons in lower energy levels closer to the nucleus repel and shield the electrons in the outermost shell or energy level of the atom.

Chlorine>Bromine>Iodine.

6 0
4 years ago
Read 2 more answers
The topsoil layer has the greatest concentration of organic matter. The subsoil generally lacks organic matter, but it does rece
zmey [24]

Answer:

C. the C horizon likely has a rockier texture than the topsoil and subsoil.

Explanation:

because i did it on study island

3 0
3 years ago
A high-speed railway car goes around a flat, horizontal circle of radius 480 m at a constant speed. The magnitudes of the horizo
kvv77 [185]

Answer:

Net force ( F ) = 208 N.

Speed of car ( v ) = 68.58 m/s.

Explanation:-

The radius ( r ) = 480 m.

Mass of passenger ( m ) = 65 kg.

Horizontal force ( f_{x} ) = 208 N.

Vertical force ( f_{n} ) = 637 N.

Net vertical component of force ( f_{x} ) = m*g - 637   = 65 * 9.8 - 637 =  0 N.

a ) magnitude of net force .

F = \sqrt{f^{2} _{x} + f^{2} _{y}  }   = \sqrt{208^{2} + 0^{2} }   = 208 N.

b) The speed of car.

f_{n}  = \frac{m*v^{2} }{r}    where v is the velocity.

637 = \frac{65 *v^{2} }{480}

v² = 4704

v = 68.58 m/s.

6 0
3 years ago
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