Which major gas in today's atmosphere was introduced by living organisms about 2.7 billion years ago?

What is a classification key? dichotomous key? Give the dichotomous key of the shark families.

4. The density of water is 1g/ml. Knowing this, do you think either the dice or book would float in water? Why or why not?

When rounding to the nearest 10 what is the greatest whole number that rounds to 7670

A population is A. all individuals of a single species that exist together in a given region. B. all similar animal species that live in the same ecosystem. C. all plant species that exist in a single region at a single time. D.

Which of the following is a detrivore? A. Cow B. Cat C. Fungus D. Radish

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.

Why was nucleic acid disregarded for so long as the molecule responsible for the transmission of hereditary information?

Sally's estimated energy requirement, based upon her age, height, and weight, is approximately 2000 kcalories per day. What is the maximum number of kcalories per day that she can consume to lose 3 pounds per month. Assume 1 month is 30 days. a.