The answer is b 15 14 13 and 12
Plants need nitrogen in order to grow. Nitrogen is abundant in the earth's atmosphere, but plants cannot use it in that particular form (nitrogen gas). Certain bacteria which reside on some plant roots are able to change atmospheric nitrogen into a form that plants can use (ammonia).
Answer:
A
Explanation:
All systems work together to do-- anything really. Especially to move-
Macrophages are a type of the White Blood Cells that is a part of the immune system of the body. Macrophages are the first line of defence. They engulf the foreign bodies, foreign particles, cancerous cells and infected cells. They do it by searching for a protein marker on the surface of these foreign bodies. When the marker is absent they attack these bodies by performing phagocytosis.
Langerhans cells present on the skin are specialised macrophages that form the first line of defence.
Answer:
Lactose present, glucose absent.
Explanation:
Lac operon may be defined as a cluster of genes that regulate the metabolism of lactose in bacteria. The bacteria always prefer glucose if both glucose and lactose is present in the medium.
The conditions that causes the maximal expression of lactose is the presence of lactose and absence of glucose. This is due to the action of catabolite activator protein and cyclicAMP.
Thus, the correct answer is option (1).
