What is the best description of organisms of the Precambrian era?

A. land plants and animals

B. Dinosaurs and primates pice mammals

C. Single celled organisms and soft, boneless animals

D. Ferns and flying reptiles

The substance that enters earth cycles and does harm to living things

Must all ecosystems have quaternary consumers?

Where are your genes found? A. your alleles B. your cytoplasm C. your ribosomes D. your chromosomes < - - my answer What is the shape of DNA called? A. nucleotide B. double helix < - - my answer C. chromosome D.

How did improving treatment of patients with antibiotics lead to a new problem?

What is it called when two molecules join together?

Which of the following is a constructive process? deposition detachment transport plucking

Coal deposits were formed from? A. Plant life in ancient B. Ancient plankton and marine life C. Freshwater organisms from the last 100,000 years D. Modern plants and animals

According to the Hardy-Weinberg principals, which of the following can prohibit genetic equilibrium?

Rickettsia are obligate intracellular parasites that are transmitted by arthropods. In which of the following places would you most likely find the parasites living in the host organism during the course of infection? A.

How are viruses able to move between species?