During which epoch did scientists infer that earliest grasses first appeared on earth?

Which of the following best describes how a cell's DNA can change through mutations? DNA segments from broken-down prokaryotic cells are taken in and incorporated into the DNA of living cells.

Identify the arrows that indicate heat being trapped by greenhouse gases.

Where does protein synthesis take place? a. in the nucleus b. on smooth endoplasmic reticulum c. on ribosomes d. in the nucleolus?

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells? A. rough ER B. smooth ER C. Golgi apparatus D.

Enzymes are proteins that speed up reactions by 1. providing an additional energy source 2. supplying additional molecules for the reaction 3. removing inhibitors that slow down reactions 4. lowering the amount of energy required

When fats first reach the duodenum what their presence stimulates the release of which hormone from the intestinal mucosal cell?

Ocean-dwelling chemoheterotrophic bacteria that generate energy via aerobic respiration are dependent on the presence of photoautotrophs like cyanobacteria because:

Nucleotide are composed of phosphate group, a sugar, and a nitrogenous base. DNA is made up of long strands of nucleotide. which part if the above molecule can differ between nucleotide? A. the sugar B. the phosphate group C. the nitrogen group D.

2 atp molecules are needed to start A) the krebs cycle B) gyycolysis C) the electron transport chain D) none of the above

If earth is about 4.5 million years old which statement is true