After the third dose -- given at age 6 months -- your child will be 80% to 85% immune to whooping cough for 3 to 5 years. Everyone -- including adults -- from age 11 up should receive a booster vaccine, called Tdap. It's a combined tetanus, diphtheria, and pertussis booster vaccine.
How many chromosomes are in the nucleus of an onion root cell? There are 8 chromosomes in the nucleus of an onion root cell. The cells are undergoing mitosis, during which the amount of DNA is doubled even as the number of chromosomes â¦ remains constant. How many chromosomes do onions have?
In mitosis, the DNA is duplicated in interphase and creates two identical cells with 46 chromosomes in them. In meiosis, the cell divides the chromosome number in half and re â¦ sults in 4 different sex cells with 23 chromosomes in them. 1 person found this useful.