Un niño que ha enfermado de paperas o varicela, no desarrollará estas enfermedades en una segunda oportunidad, porque:

I. la piel, mucosas y lágrimas impiden el ingreso de los microbios.

II. en el primer contacto adquirió anticuerpos.

III. interviene la inmunidad Adaptativa, la cual presenta “memoria”.

IV. su sistema defensivo está preparado frente a una segunda exposición

a. I y II son correctas

b. III y IV son correctas

c. II, III y IV son correctas

d. I, II y III son correctas.

What is the difference between sex-linked traits and autosomal traits in humans? a. sex-linked traits can only be passed from fathers to sons, while autosomal traits can be passed on from both parents to offspring of any sex. b. sex-linked traits are passed on through the x and y chromosomes, while autosomal traits are passed on through the other 22 chromosomes. c. sex-linked traits only affect females, while autosomal traits affect both males and females. d. sex-linked traits refer to genes that are on the x and y chromosomes, while autosomal traits refer to genes on all 23 chromosomes.

During convection, less dense fluid rises and denser fluid sinks.

Which type of transport is responsible for oxygen entering into blood cells? a. vesicle b.passive c. facilitated d.active b.passive