What do all ecosystems have?

A. biotic p21 only

B. abiotic p21 only

C. producers only

D. biotic and abiotic p21

in 1994, naturalists in Australia discovered a new genus and species of conifer, Wollemia nobilis, growing in a remote area not far from the city of Sydney. This was the first new conifer discovered since 1948.

Which of the following protists have shells?

In an ecosystem, which is NOT a density- dependent limiting factor? A) predation B) parasitism C) competition D) natural disaster

Three muscles in the human body that have the same name

Which age group presents the greatest risk for alcohol or drug-related fatalities?

The rapid depolarization phase of the action potentials of myocardial contractile cells is due primarily to which ion (s) ?

Echinoderm reproduction typically is a. sexual reproduction by budding. b. sexual reproduction with internal fertilization. c. by regeneraton. d. sexual reproduction with external fertilization.

Which is an abiotic factor of the boomslang's environment? A. the sun B. the tree C. the grass D. the people

A double-stranded molecule of DNA has 80 T nucleotides and 110 G nucleotides. What is the TOTAL number of nucleotides in this molecule of DNA?

Why is an angioplasty an incorrect treatment for an aneurysm? A) Aneurysms cannot be treated. B) An angioplasty may rupture the blood vessel wall. C) An angioplasty can have dangerous drug reactions. D) Aneurysms are treated only with pacemakers.