Two characteristics used to define mammals include

a. mammary glands and scales.

b. mammary glands and hair or fur.

c. mammary glands and sweat glands.

d. sweat glands and a four-chamber heart.

Why might having an excretory system that excretes urine be a disadvantage in a desert environment? how can desert animals overcome this disadvantage?

What is the number of characteristics that define a living thing

Based on the benefits received from the Three Gorges Dam, China is planning four new dams for the Yangtze River further upstream.

Match these machines with their examples. 1. seesaw wedge 2. pencil sharpener third-class lever 3. bottle opener wheel and axle 4. forearm second-class lever 5. nail first-class lever

How many species of animals havebeen extinct?

Drag each label to the correct location on the diagram. Each label can be used more than once. An incomplete diagram of the rock cycle is shown below. Use the labels to correctly complete the diagram

Deepest place in the seafloor is called the

Monohybrid cross is made between plants that

Which statement best describes an aerobic heterotroph

What disease disables the bodys immune system?