Implantation is the major sign of pregnancy for various women, it is a stage in which a zygote of fertilized egg limplants into the wall of the uterus.
Implantation usually takes place 6 to 10 days post ovulation, or day 20 to 24 of a menstrual cycle. However, it can take place a few days later or earlier. Once fertilization takes place, the egg remains the fallopian tuve for three days prior of getting inside the uterus and starts to implant itself to the walls of the uterus.
Yes
they are
i am sure of it
Answer:
The correct answer is - option B. They are small because they lack a nucleus.
Explanation:
Red blood cells or erythrocytes are specialized cell that produce in bone marrow and have specific role such as carrying oxygen from lungs to deliver it to the various organs and carry out carbon dioxide.
In mammals these cells lack cell organelles such as nucleus and mitochondria, a major factor that determined its smaller size. The size of RBC are move through narrow vessels throughout a organism because of its specific size and shape that provide it space for hemoglobin and allow to be flexible and bend to move through narrow vessels.
Thus, the correct answer is : option B. They are small because they lack a nucleus.
