The body has a number of systems that protect against infection. Which of the following correctly orders four of these systems from most to least foundational?
Choose 1

A. B cell, lymphatic tissue, lymph node, lymphatic system

B. B cell, lymphatic tissue, lymphatic system, lymph node

C. lymphatic tissue, B cell, lymph node, lymphatic system

One statements is an example of a scientific observation. another statement is an example of a scientific explanation. identify the correct statement for each category to illustrate how scientific explanations are inferred from scientific observations.

Cathy hypothesized that corn would not grow in mud. to test this hypothesis, she took corn kernels and placed 5 in mud, 3 in soil, and 2 in water. to her surprise, the kernels in the mud grew faster than the kernels in the soil. what error might have caused these unexpected results? a. wrong hypothesis b. not enough variables c. undefined control d. too many variables

Why has two different alleles for the same trait?