Which of the following scenario demonstrates apoptosis? 1. An immune Self-destructs once it is no longer needed by the immune system

2.a severe burn causes skill cell to die

3.webbing between an embryos toes is eliminated during embryological development

4. Muscle fibers are signaled to contract and move

Which of the following is a difference between a food chain and a food web? selected: a. food webs contain both plants and animals. food chains only contain animals.this answer is incorrect. b. food webs show energy transfer. food chains show which animal eats which animal. c. food webs separate organisms by tropic level. food chains do not. d. food webs are a complex patterns of energy flow. food chains only show one line of energy flow.

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

Which layer will become saturated first when rain falls?