Fossil evidence indicates that the following events occurred in what sequence, from earliest to most recent?

1. Protostomes invade terrestrial environments.

2. Cambrian explosion occurs.

3. Deuterostomes invade terrestrial environments.

4. Vertebrates become top predators in the seas.

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#Question id: 11970

#Unit 7. System Physiology – Animal

Why do the cells of the digestive system secrete proteolytic enzymes, such as pepsin, in their inactive forms?

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#Question id: 5354

#Unit 8. Inheritance Biology

Eye color gene link with X chromosome, If red eye color gene is dominant over white eye color gene. Which of the following genetic cross and their respective offspring is not correlated?

	Genetic cross	Phenotype of offspring
1	Heterozygous Red eye female  X   Red eye Male	All male red eye
2	Heterozygous Red eye female  X   white  eye Male	Male either red  or white eye
3	Homozygous Red eye female  X   white eye Male	All female red eye
4	Homozygous Red eye female  X   Red  eye Male	All male red eye

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#Question id: 2265

#Unit 2. Cellular Organization

Passage through pores in the nuclear envelope is restricted primarily to

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#Question id: 10942

#Unit 7. System Physiology – Animal

A 45-year-old man presents to the emergency room with a 2-week history of diarrhea that has gotten progressively worse over the last several days. He has minimal urine output and is admitted to the hospital for dehydration. His stool specimen is positive for parasitic eggs. Which type of WBCs would have an elevated number?

TLS Online TPP Program

#Question id: 19102

#Unit 6. System Physiology – Plant

Phytoplasmas are specialized bacteria that are obligate parasites of the phloem tissue. They are mainly spread by these insects except;