The measles virus and rubella virus are two separate viruses. They have different DNA and RNA structures, and the vaccination for the measles virus only "knows" how to attach itself to measles and destroy the virus. It doesn't know how to attach itself to the rubella virus to destroy it, as the vaccination is needed to inform it how to.
The advantage of vaccinating a large amount of the population is that it reduces the chance someone will catch sickness by a great amount, and can possibly eradicate the virus.
Answer:
Double fertilization
Explanation:
The phenomenon of double fertilization is unique to flowering plants (i.e., angiosperms). Each pollen grain produces two male gametes (sperm cells), one of which fertilizes the egg to form the zygote, whereas the other sperm fuses with polar nuclei in the female gametophyte in order to form a triploid cell (3n) called endosperm. Subsequently, this endosperm will support embryonic growth by supplying storage nutrients and by serving as a mechanical barrier during seed development and germination.
Saliva contains Salivary Amylase, which helps in breakdown of sugar.
So, correct choice is (a) Amylase.
nuclear envelope contains a double membrane in order to protect the nucleus.
