About how many major mass extinctions have there been in the earth's history

Two atoms are isotopes of the same element. Which of the following should be different for these two atoms? A. The behavior in a chemical reaction B. The number of neutrons C. The type of element D. The number of protons

What form of interaction is taking place when a shark devours a seal

When cells respond to an extra cellular signal, they convert the incoming information from one form to another. This process is called signal a. induction b. interference c. transduction d. transformation

The interdependence of body systems is essential because?

Which of the following statements is true with respect to protonema? It gives rise to sporophyte. It produces male gametes. It gives rise to gametophyte.

Bacteria and viruses can multiply on living and nonliving surfaces. question 71 options:

Why didn't the three candles stop burning at the same time after the jars were placed? What does this tell us about the rate of a combustion reaction?

Which statement about the tumor suppressor gene p53 is false? (A) It is required for apoptosis in response to DNA damage. (B) It blocks cell cycle progression in response to DNA damage. (C) It plays a role in up to 50% of human cancers.

Which of the following is not an example of a heterotroph

Coral reefs only form in ocean waters between 30 N and 30 S. The reefs are confined to shallow water because?