<h2>Answer:</h2>
The option D is correct.
<u>B cells are memory producing cells.</u>
<h3>Explanation:</h3>
As B cells are the specific receptor cell, after immunity to certain infection of the foreign particle, there is a function of acquired immunity is the protection of the body from that particular infection for the whole life which is done by <u>memory cells of B lymphatics.</u>
Answer:
False
Explanation:
Action potential will only be fired when the memebrane potential is above the threshold level.
This follows the all-none -principle.
No matter the strenght of stimulus if the magnitride is not upto the threshold level,No action potential will.be generated.
An example is the flushing of water closet or lavoratory.No mater one tried to flush,if the water in the closet does not fill up to the threshold for flushing,,to propel flushing. not flushing will take place.
It develops from an outer fold on the surface of the yolk sac<span>, which lies outside the </span>vitteline envelope<span> and is developed by the </span>follicle cells<span> while the </span>egg<span> is in the </span>ovary<span>.</span>
Answer:
Option D
Explanation:
Cyanobacteria preserve its photosynthetic pigments in the thylakoids which allows masking of green of chlorophyll a and other accessory pigment i.e phycobiliproteins (phycocyanin, allophycocyanin and phycoerythrin).
Chlorophyll a is mainly responsible for harvesting light for photosynthesis. Phycocyanin is blue in color, allophycocyanin is blue in color and phycoerythrine is red in color. These together harvest light in the green, yellow and orange part of the spectrum which cannot be used by other phytoplankton species
Hence, option D is correct
