Answer:
The boat moves backward when the person jumps out of the boat is due to the reaction force of the person on the boat in the backward direction.
Explanation:
Explanation: The direction of the reaction force acting on a body due to the action of a force in a particular direction is given by the Newton's law.
Answer:
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
Explanation:
Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete cytokines that regulate or assist the immune response.
Answer:
(1) Red Blood Cell
(2) Enzymes
Explanation:
(1) Oxygenated Red Blood cells transport oxygen from the lungs through the body using the arteries as a channel of movement to all organs.
(2) Enzymes are proteins that catalyze chemical reaction in the digestion of food so as to break food down into a form which can be absorbed by the body.
Cat (Australia); lots of cats became feral and they reproduce very fast. They became the apex predator and the native species have no defense system for them, so the cats brought tens of species on the verge of extinction (mainly placental mammals).
Fox (Australia); became an apex predator in the lack of competition, and damages the populations of native small placental mammals.
Hair (Australia); reproduces much quicker than the native species of mammals, increased significantly in numbers, and out competes the native species for the food sources.
African bee (the Americas); much more aggressive and stronger than the native bees and systematically kills their populations.
Grey squirrel (Britain); reproduces quicker than the red squirrel, is bigger, and out competes for food, brought it on the verge of extinction.
