Why all organisms ingest food in …

Ingestion is the intake of food into the body through mouth. Method of ingestion, i.e. taking of food, varies from one animal to another.

Different organism takes food in different ways.

A humming bird sucks nectar of plants.
Human beings use their hands to put food into their mouth and swallow the food after chewing.
Infants of human and many other animals feed upon their mother’s milk by sucking them.
A snake swallows the animals they prey upon without chewing them.
A frog captures prey with its sticky tongue.
An earthworm uses its muscular pharynx to swallow its food.
Spiders weave sticky web in which small insects get stuck.
Some aquatic animals filter tiny particles floating nearby and feed upon them.
Amoeba, a unicellular animal, engulfs tiny particles of food by using pseudopodia. Amoeba surrounds the food by pseudopodia and then makes a food vacuole to engulf the food.
In multicellular organisms; like hydra there are numerous tentacles around their mouth. Hydra uses tentacles to surround its prey and kill them with its stinging cells. Then the food is pushed inside the body cavity.