Fraternal twins develop when:
A) two eggs are fertilized by one sperm.
B) multiple ovulations occur, and two eggs are fertilized.
C) one egg is fertilized by one sperm, but the resulting cells separate from one another and continue development.
D) one egg is fertilized by two sperm.
Answer: B
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horsetails a. as pot scrubbers. b. as sandpaper. c. for decoration. d. for kindling. e. for food.
Which of the following is a type of cytokine?
a. complement protein b. mast cell c. immunoglobulin d. lysozyme e. tumor necrosis factor
Movement of body parts directly requires the
a. endocrine system and nervous system. b. muscular system and skeletal system. c. skeletal system and digestive system. d. muscular system and cardiovascular system. e. nervous system and endocrine system.
Cancer can result from:
A. problems metabolizing oxygen B. abnormal pancreatic functioning, which can alter hormone levels C. the adrenal glands releasing insufficient cortisol D. stress, which releases hormones that suppresses immune functioning