Most eukaryotic genes contain noncoding sequences called that are interspersed with the coding sequences.
a. introns b. exons c. codons d. spacers e. spliceosomes

Which of the following is a possible reason for sleep? a) growth b)digestive c)speed d)intelligence

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which sentence best describes the relationship between chlorophyll and the chloroplast? a.)chlorophyll is a chemical found in a chloroplast. b.) chloroplast is a chemical found in a chlorophyll. c.) both chlorophyll and chloroplasts are found in animals. d.) both chlorophyll and chloroplasts make carbon dioxide.