The process by which a cell engulfs liquid droplets is: MCQ with Answer and Explanation

Explanation:
Adrenaline (epinephrine) from the adrenal medulla mediates the 'fight-or-flight' response, increasing heart rate, contractility, and blood pressure. Acetylcholine slows heart, insulin lowers glucose, melatonin induces sleep.

Explanation:
The choroid plexus, located in the ventricles of the brain, is a network of capillaries and ependymal cells that secretes cerebrospinal fluid (CSF). CSF cushions the brain, removes waste, and maintains chemical environment. Meninges are protective coverings, corpus callosum connects hemispheres, pineal secretes melatonin.

Explanation:
Mutualism is a symbiotic interaction where both species benefit (+/+). Examples: Rhizobium-legume association, lichens, mycorrhizae, and oxpecker-rhino. Parasitism benefits one at the expense of the other (+/-), commensalism benefits one without affecting the other (+/0), amensalism harms one without benefit to the other (-/0). Mutualism is crucial for ecosystem functioning.