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 humans, during interphase, before DNA replication, there are 46 chromosomes. After DNA replication, there are 92 chromosomes (4 sets of 23). During prophase, metaphase, and anaphase, there are 92 chromosomes. During anaphase, the 4 sets of chromosomes separate into 2 sets of 23 and move to opposite poles. There are still 92 chromosomes in the cell.