What are the four requirements for life?

What type of cell is produced after fertilization occurs and the gametes combines ?

An ecologist studied the same species of deer during the summer and the winter. she noticed that during the summer, when there was plenty of food, the deer were energetic and playful. however, during winter when food was scarce, the deer moved more slowly and did not run unless they needed to escape a predator. which scientific fact is best supported by her observations?

Read each description below and determine to which stage of sleep each pertains. then click and drag each box into the appropriate category below.