The technique of communication by signs made with the fingers is called

Answer: Option B

Explanation:

The study of relation of animals and plants to their surroundings, animate and inanimate is called Ecology.

The study of insects is called Entomology.

The study of inscriptions is called Epigraphy.

Answer: Option D

Explanation:

The study of ancient writing systems and the deciphering and dating of historical manuscripts is called Paleography.

A person's facial features or expression, esp. when regarded as indicative of character or ethnic origin is called Physiognomy.

The production of silk and the rearing of silkworms for this purpose is called Sericulture.

Answer: Option C

Explanation:

The supposed communication of thoughts or ideas by means other than the known senses is called Telepathy.

The study of caves is called Spelelogy.

The branch of science concerned with earthquakes and related phenomena is called Seismology.

Answer: Option D

Explanation:

The study of bacteria is called Bacteriology.

The study of the movements and relative positions of celestial bodies interpreted as having an influence on human affairs is called Astrology.

Cultivation of trees and vegetables is called Arboriculture.

Answer: Option A

Explanation:

The study of sound is called Acoustics.
The science or art of flight is called Aeronautics.
The philosophy of fine arts Aesthetics.
The science of soil management is called Agronomy.