When a plant grows toward sunlight it is called positive phototrophism.
1.Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills either on side of the pharynx.
2.Gills are branching organs located on the side of fish heads that have many, many small blood vessels called capillaries.
3.The colour is red
4. A Gill filaments project from each arc between the dorsal upper and ventral lower surfaces of the filaments.
Answer:
D
Explanation:
Lymphocytes are the second line of defence
First line of defence indiscriminately defends against all pathogens unlike secondary response which is targeted. First line of defence refers to the external body components like skin, secretions from the body in the alimentary canel
Mucus traps pathogens. Stomach acid kills pathogens
