The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary (K–T) extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago.
Answer:
In biology, a cladogram can be described as a diagram which shows evolutionary relationships among different organisms. A cladogram shows which organisms share evolutionary history and which organisms are more closely related to one another.
<em>The cladogram in the above picture shows that the limbs originated after the jaws. </em>
The cladogram shows that amoeba was a common ancestor to sponges, earthworms, salmon, lizards, kangroo and cats.
Answer:
they use to live
Explanation:
As they breath out carbon dioxide the plants take in the carbon dioxide and make air with it. Animals also use air to do their day to day things like eat.
Answer:
1) Macrophages ingest antigen 2) Helper T cells are activated 3) B cells differentiate into plasma cells and memory cells.
Explanation:
Innate immunity and adaptive immunity provide protection against foreign invaders. Innate immunity is non specific and adaptive immunity is specific immune response; includes the production of antibody after a sequence of events.
- When an antigen enters the body the phagocytic cells such as macrophages and dendritic cells ingest the antigen by a process called as phagocytosis. These cells act as antigen presenting cells and present it to T cells.
- T cells are of two types T helper cells and T cytotoxic cell. T cytotoxic cells killed the affected cell such as affected by virus while T helper cells signal for the production antibodies.
- Antibodies are produced from the plasma cells while memory cells act as record keeping. The plasma cells are stimulated by interleukins.
Answer:
it ensures the transmission of traits from one generation to the next.at thesame time,it is a key process that introduces genetic variation into the traits that offsprings inherent from their parents.
