Questions

Caverns are openings in the ground. Some famous caverns in the United States are Mammoth Cave, Carlsbad Caverns, Wind Cave, and Luray Caverns.

When rainwater trickles down through the soil, it carries carbon dioxide from the air with it. This turns acidic as it moves through the soil, joining with carbon from decaying plants. This acidic rainwater then eats away at, or erodes, the rock under the ground, forming a cave or cavern. For this process to occur, the rock must be the right type; limestone, dolomite, and gypsum are common.

Squirrels typically build leaf nests in the summer by weaving together small branches they've gnawed off of trees. These nests are lined with grass, moss, leaves and pine needles. Both male and female gray squirrels of all ages participate in building dens.
 

A Clock has a face, but no eyes. It has 3 hands i.e, hours, minutes and seconds hands but no arms.

A modem is nothing but short for Modulator and Demodulator. It is used mostly for connecting to the internet.

A modem is a device or program that enables a computer to transmit data over, for example, telephone or cable lines. Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.

True. Hormones are chemicals secreted and regulated by the endocrine system.