Which of the following occurs

while homologous chromosomes

are paired up?

A. They create 2 haploid cells.

B. They contain 6 chromatids.

C. They exchange portions of their DNA.

D. They produce two diploid cells.

Nitrogen fixation is a natural process by which inert or unreactive forms of nitrogen are transformed into usable nitrogen. why is this process important to life

Ehlers-Danlos syndrome is a genetic disorder that affects collagen. Collagen supports and maintains connective tissue in the body.

The hypothesis the evolution occurs at a slow constant rate is known as A slow-motion b-adaptation C - slow motion D gradualism

Which group of organisms is classified a population? a) a group of skunks living in the same forest b) robins in north America c) all dogs in china d) different kinds of butterflies living in the same patch of rain forest

Select the correct statement about lymphoid tissue. A) Once a lymphocyte enters the lymphoid tissue, it resides there permanently. B) Lymphoid macrophages secrete antibodies into the blood.

Of the events listed here which comes the latest in ciliate reproduction? note: not all events in the reproduction are listed.

Is more oxygen produced with or without oxygen?

What is the most important laboratory procedure to follow before entering the lab area? A. Know the location of any stock solutions or general supplies that will be needed for the lab. B.

The element sodium (Na) has an atomic number of 11 with one outer valence electron, this element would likely form A.) An anion B.) A cation C.) An inert gas D.) A covalent bond

Which weighs more (in grams), a mole of gold (Au) or a mole of bismuth (Bi) ? Explain you answer