Explanation

Folic acid nutrient deficiency causes megaloblastic anaemia.

Explanation

Cyclic AMP is a second messenger molecule that is involved in intracellular signaling pathways, not extracellular signaling.

Explanation

• Adrenaline requires a cell surface receptor for its action.
• Adrenaline, also known as epinephrine, acts through cell surface receptors called adrenergic receptors to exert its physiological effects.

Explanation

Nitrogen is an important mineral nutrient for plants and is essential for their growth and development. 

Explanation

• Vitamin A (specifically, retinal) is necessary for the formation of rhodopsin, a light-sensitive pigment in the retina of the eye.
• Rhodopsin is responsible for black-and-white vision and is found in the rod cells of the retina.
• Vitamin A deficiency can lead to night blindness, a condition where people have difficulty seeing in low light environments.

Explanation

All of the options listed can be transmitted via infectious droplets:

• Rubella (German measles) is an airborne disease spread through droplets when an infected person talks, coughs, or sneezes.
• Common cold is a viral infection spread through airborne droplets when an infected person talks, coughs, or sneezes.
• Influenza (flu) is also an airborne disease spread through droplets when an infected person talks, coughs, or sneezes.

Infectious droplets are a common mode of transmission for many respiratory pathogens, including viruses and bacteria.

So, none of the above options are incorrect, and the correct answer is indeed "None of the above".

Explanation

• "In plants, the cell signaling occurs through phytohormones": True. Phytohormones, such as auxins, gibberellins, cytokinins, ethylene, and abscisic acid, play a crucial role in plant cell signaling, regulating various physiological processes like growth, development, and responses to environmental stimuli.
• "Cell signaling is used to study the context of human diseases": True. Cell signaling is indeed used to understand the underlying mechanisms of various human diseases, including cancer, diabetes, neurological disorders, and many others.
• "Cell signaling is used to study the signaling between cells of an organism": True. Cell signaling is essential for understanding how cells communicate with each other to coordinate various physiological processes within an organism, including development, homeostasis, and responses to stimuli.

So, all three statements are true, making "All of the above" the correct answer!

Explanation

Pepsin is a digestive enzyme that breaks down proteins into smaller peptides and amino acids.

It is produced in the stomach and is activated by hydrochloric acid.

Pepsin is essential for the digestion of protein-rich foods such as meat, poultry, fish, eggs, and dairy products.

Explanation

The system of arranging taxonomic categories in a descending order based on their relationships with other group of organism is called hierarchy of categories.

There are seven main categories of hierarchies namely,

Kingdom, Phylum, Class, Order, Family, Genus and

Species is the basic unit of classification

Explanation

Roots are food storage organs and hence food is transported to them from the leaves.

Hence roots are sinks.

Also, all young growing parts are considered as sinks as they have the highest rate of metabolism and hence require food.

Developing fruits and the apical meristem are growing parts, and hence act as sinks.