How many times has earth's magnetic field reversed polarity in the last 4 million years? (Its not 5)

Sickle-cell disease is a debilitating disease that results from being homozygous recessive for the "sickle-cell allele" of a hemoglobin gene. Why is the allele present and even common in many human populations?

Question 3 Which of the following isotopes is not commonly used for dating objects? carbon-14 phosphorus-32 potassium-40 rubidium-87

A (n) is a heterogeneous mixture in which solid particles settle.

The time it takes the Moon to go through a complete cycle of phases is closest to days. OA) 20 OB) 24 OC) 27 OD) 30

How can you use the word 'receptor' in a sentence? (cell biology)

Acid precipitation is an agent of what kind of weathering?

When do scientists consider a hypothesis valid? A. when the hypothesis is testable B. when the hypothesis is published in a scientific journal C. when more than one person supports the hypothesis D. when experimentation shows it to be true

In cherry trees, white flowers are dominant over pink flowers. cross a homozygous dominant tree with a purebred recessive tree. what is the phenotypic ratio of the offspring? a. 4 ww b. 4 white selected: c. 4 ww d. 4 pink

What happens to Earth when it is farthest from the sun? A) It moves fastest, B) It stops rotating, C) It moves slowest. D) It stops revolving

Deer ticks are responsible for spreading Lyme disease. This organism, which feeds on the blood of warm-blooded organisms like mice, deer, and humans, is best described as a (1) predator (3) parasite (2) scavenger (4) host