Questions

Tax that uses the same rate for all income levels is proportional tax.

When water is cooled from 4°C to 0°C, its density decreases.

When water cools from 4°C to 0°C, ice crystals begin to form because the water is approaching its freezing point. When water freezes, the water molecules form a lattice that increases the volume. As a result, the density decreases. This is why ice will float on top of water; ice has a lower density than the water.

Molten rock inside the earth is called Magma.

A clade is a group of ancestral species and all its descendants. Hence it is a branch of one same species and so monophyletic.

The main source of organic matter in soil is the plant and animal tissue that decompose at each level of breakdown.

Sending a message to a group is called multicasting, and its routing algorithm is called multicast routing