As nouns the difference between ecosystem and biocenose

is that ecosystem is a system formed by an ecological community and its environment that functions as a unit while biocenose is biocoenose, biocenosis.

As adverbs the difference between extremely and severely

is that extremely is to an extreme degree while severely is in a severe manner.

Sentinent is often a misspelling of sentient.

Sentinent has no English definition.

As an adjective sentient

is conscious or self-aware.

As a noun sentient

is lifeform with the capability to feel sensation, such as pain.

As nouns the difference between welfare and beneficence

is that welfare is (uncountable) health, safety, happiness and prosperity; well-being in any respect while beneficence is an act of philanthropy, a kind deed; an act which benefits someone (else).

In obsolete terms the difference between absent and tardy

is that absent is absentee; a person who is away on occasion while tardy is criminal; guilty.

As a preposition absent

is in the absence of; without.

As an adjective symmetric

is symmetrical.

As a noun metronome is

a device, containing an inverted pendulum, used to mark time by means of regular ticks at adjustable intervals; an electronic equivalent that emits flashes.

As an adjective festive

is having the atmosphere, decoration, or attitude of a festival, holiday, or celebration.

As a noun festivity is

(often|pluralized) a festival or similar celebration.

As verbs the difference between fun and torture

is that fun is give while torture is .

As a preposition fun

is for, on behalf of.

As nouns the difference between student and consumer

is that student is student while consumer is one who, or that which, consumes.

As an adjective avid

is enthusiastic; passionate; longing eagerly; eager; greedy.

As a noun ambition is

ambition for some particular achievement.