Swelling in the feet and ankles is a very common symptom and can have a variety of causes. One way that doctors pinpoint the cause of swelling is by noting whether it is occurring in one limb, or in both equally. In many cases, the cause of swelling is something that requires medical attention, such as an infection or injury.
Pollination and Fertilization of Plants Visit a flower garden in the summer and youâll see and hear lots of activity. Bees are buzzing and busily moving from flower to flower.
There are two mechanisms by which fertilization can take place. 1  The first is external fertilization (the eggs are fertilized outside of the body), and the second is internal fertilization (the eggs are fertilized within the female reproductive tract). While fertilization is necessary for organisms that reproduce sexually, individuals that reproduce asexually do so without the need for fertilization.