Pollen tube growth is one of the most fascinating—and essential—phenomena in the life cycle of flowering plants. After a compatible interaction between pollen grains and the stigma surface, the pollen germinates and forms the pollen tube, which grows through the stigma, style, and transmitting tract to deliver the sperm cells to the ovule."
2) Although pollens of many species germinate in simple aqueous media, stigmas do not provide satisfactory sites for the germination of most foreign pollen... Stigmas not only provide the proper conditions for the germination of pollen from their particular species, they actively inhibit the germination of pollen of many unrelated species.
The lower limb bones are attached to the axial skeleton by a ring of bones called the pelvic girdle. The pelvic girdle consists of the right and left hip bones.
The bones of the head and trunk of the vertebrate form the axial skeleton.
I think its autotrophs and asexual
ex... autotroph- plants asexual- penguins
Directly The immune system is designed to defend the body against foreign or dangerous invaders. Such invaders include
Microorganisms (commonly called germs, such as bacteria, viruses, and fungi)
Parasites (such as worms)
Cancer cells
Transplanted organs and tissues
To defend the body against these invaders, the immune system must be able to distinguish between
What belongs in the body (self)
What does not (nonself or foreign) normal immune response consists of the following:
Recognizing a potentially harmful foreign antigen
Activating and mobilizing forces to defend against it
Attacking it
Controlling and ending the attack
If the immune system malfunctions and mistakes self for nonself, it may attack the body’s own tissues, causing an autoimmune disorder, such as rheumatoid arthritis, Hashimoto thyroiditis, or systemic lupus erythematosus (lupus).
<span>The difference that you are searching for is the addition of Appendages. They appeared in Cambrian animals and were used to increase their physical capabilities like when sensing and processing the information found in the environment. Common appenadges found in animals are things like antennae found in insects that are used to help them communicate or notice things or similar things.</span>