What is an example of an autotroph and a heterotroph?

Why do the cells inside of your stomach get replaced every few days, but other cells in your body can live for weeks, months or even years?

Which structure carries the semen to the penis? sperm duct glands scrotum testes

Which feature may form as slightly acidic surface water and groundwater dissolve carbonate rocks such as limestone? A. lakes B. caves C. mountains D. alluvial fans

Plant-Deer-Tiger the first step in the energy chain that created the bonds of proteins in tiger's muscle cells in the food chain shown above the A. Deer the tiger ate B. Plant the deer ate C. Protons the sun made D. Carbohydrates the plant made

What is the oldest planet in the universe? How did scientists arrive at this conclusion?

How can we use rocks to determine how an area used to look in the past?

What type of bonds connect the deoxyribose sugars to the phosphate group?

What are proteins made up of?

What are at least 5 important words associated with the water cycle? What do they mean? Why are they important?

Which of the following organisms is NOT a protist? a. water molds c. Amoebas (protozoans) b. Escherichia coli d. Diatoms (algae)