Energy flow is said to be a one way street. Why?

Energy flow in an ecosystem is:

Respriatory system of cockroach is formed of spiracels and tracheal intercom. Why it is said to be more efficient than that of earthworm? Why inspritation of cockraoch is said to be a passive process while it is an active process in man?

Discuss the energy flow in a food chain formed of three tropic levels.

Wheatstone bridge is said to be balanced, when no current flows through the.......

How energy flow occurs in an ecosystem?

Pyramid of energy in an ecosystem can never by inverted. Why?

Why are males said to be heterogametic?

Why it is said that nuclear forces are saturated forces?