امتحان ساينس- رابعة ابتدائي - مقرر اكتوبر -الوحدة الاولى

.........is a pattern that has a specific meaning agreed upon by the sender and receiver.

Glow beetles belong to flying insects .

In ancient times, people used .......... to communicate over long distances using the sense of sight.

The Mayans made paper from ...........coated with lime.

Humpback whales make music in series of phrases in a pattern during................................... months.

..........is created by vibrating objects forward or backward in a form of sound

............ consists of many parts that work together to transfer information from one place to another.

.................collect information and send it to the brain.

The ............. in Mesopotamia   created the cuneiform writing.

......is the number of waves  that pass through a specific point in a specific time.

The ............. invented papyrus paper for writing.

The ability of beetles to emit light flashes is a kind of .....................................

If .......... sound waves pass through the same point, the wave will have a higher frequency.

Humans can communicate with fireflies using flashes.

..........is the sensation of a sound wave's frequency.