Answer:
<u>Antigenic drift</u> refers to the slow accumulation of genetic changes to an influenza virus over time.
Explanation:
Antigenic drift is defined as the mechanism by which viruses undergo variation. This mechanism involves the slow accumulation of mutations in the viral genes, that are responsible for coding the antibody binding sites. This leads to the formation of a new strain of virus, which can't be inhibited by the old antibodies. Due to this, the virus can easily spread the disease.
The antigenic drift occurs in the influenza A virus and also the influenza B viruses.
Therefore, <u>Antigenic drift refers to the slow accumulation of genetic changes to an influenza virus over time.</u>
Answer:
jssuusisiisieiwjjwjejejejejjd
The answer is the detection
of heat and touch. The integumentary system consists of the skin, nails, glands,
hairs, and nerves. The nerves are responsible for sensing stimuli including pressure, heat, and touch. Another
example of its function is acting as a physical
barrier against harmful microorganisms and excretion.
Answer:
Once the embryo sac has developed, pollination has occurred, and the pollen tube has grown into the ovary to make contact with the ovule, fertilization (fusion of egg and sperm) can occur.Typically, the pollen tube reaches the embryo sac via the micropyle (Greek, mikros + pyle = small opening), or opening, in the integuments of the ovule.. There, it discharges its sperm into the embry
Explanation:
The pollen tube enters into the ovule, through the micropyle. Inside the embryo sac, the tip of the pollen tube ruptures and the 2 male gametes are set free near the egg apparatus. Inside the embryo sac, one of the 2 male gametes fuses with the egg nucleus and forms a diploid zygote. This process is called syngamy or true fertilisation.
