Answer:
Internal Fertilization: Mammals,birds and reptiles in them the mode of fertilization is internal
External Fertilization: Amphibians and fishes used external fertilization.
Egg laying Animals;Birds,reptiles and some mammals platypus lays eggs.
Explanation:
Fertilization is a process in which a female egg (Ovum) and male egg (sperm) unite to form a zygote.A zygote is a fertilized egg which grows within an embryo.The process of fertilization is important in eukaryotes such as animals, humans,birds and plants. Fertilization divides a cell into many daughter cells by the process of mitosis and meiosis.It doubles the chromosome numbers.Fertilization are of two types internal and external.
Answer:The Cycad tree is the sporophyte.They have flagellated sperm.
Explanation:
During pollination, the contents of the megaspore divide to form many–celled gamateophyte called the endosperm and archegonium. There is a micropyle opening with a sticky fluid, which traps the wind-borne male gametophyte (microspores) which,at this time is made up of prothallus cell;an antheridial cell and a large tube cell. The trapped microspore is sucked into the archegonia chamber. Antherizoids are released, but only one penetrates each oospore and fuses with the female nucleus. The zygote is formed in the ovule and the later develops into seed.The diploid seed germinates into a new sporophyte plant and the life cycle begins again. Examples of cycad include Cycas circinalis ,Cycas celebrical and Cycas revoluta
Answer:
World Wildlife Federation (WWF)
Explanation:
They're one of the MANY organizations who help with wildlife and their habitats.
Answer:
α = 0 if β= 0
Explanation:
If both species want to persist in the same environment and their niches are also over lapping then both of the co-efficient values should be equal. There are two possibilities on these values for persistence. One is that one should compromise to the change produced by the invasive specie and two is that the new specie should compromise if he wants to stay (<em><u>Assuming that there is no competition</u></em>). In this way their niches won't overlap to a greater extent and therefore better chances of survival for both.
Answer:
Self-antigens are not recognized and attacked by the T cells.
Explanation:
In immunology, the antigens are those substances which are bound by the antibodies. The antigens can be originated from within the bodies, known as self antigens or from outside the body, known as non-self antigens. The immune system identifies and attacks non-self invaders or the foreign harmful objects present in the body. It does not attack the self-antigens under the normal conditions. This is due to the negative selection of T cells of the thymus.