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?
A human body cell would have 46 chromosomes. Since a human egg cell is a reproductive cell (sex cell), it would contain only half the number of chromosomes as a body cell. Thus, a human egg cell would have 23 chromosomes. A sex cell has half the number of chromosomes for a good reason. When two sex cells reproduce, they combine to form double the number of chromosomes. So when two cells with 23 chromosomes each reproduce, the offspring would have 46 chromosomes.