The first life on Earth, a simple, single-celled prokaryotic bacteria, appeared on life approximately how long ago? A) 4 thousand years B) 4 million years C) 4 billion years D) 4 trillion years

give two reason why it is impossible to associate some of the most obvious human traits with single genes?

Which valves produce the second heart sound when they snap shut

In the hypothesis that Chthamalus stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by Semibalanus balanoides (another species of barnacle), what could be concluded about the two species?

How did predation affect the isolated guppy populations in Trinidad?

Binucleated cells are found in onion root tips are examined under a microscope. What does binucleated mean? which part of the cell cycle is interrupted to cause this result?

Which river is associated with the settlement of ancient egypt? question 2 options: tigris ganges nile yellow

What is a binomial nomenclature? a two word system for naming organisms by using the genus and species a two word system for naming organisms by using the family and genus a two word system for naming organisms by using the order and family a two

Excess of which vitamin can cause toxic effects of excess perspiration and fishy body odor

Many children were paralyzed by polio in the 1950s. Today, polio has been reduced by 99 percent. Which statement best explains how this disease has been almost eradicated?

When looking at biodiversity threats, how do invasive species rate, wat is the higest threat to biodiversity