1. What is the first line of defense against infection for the human body?

A. white blood cells

B. saliva

C. skin

D. red blood cells

Why do scientists usually use a food web instead of a food chain?

What do stabilizing selection and directional selection have in common

The cells in our body are replaced on a weekly basis true or false

Which sphere protects Earth's surface? atmosphere biosphere geosphere hydrosphere

Before cells divide their DNA replicates to form two identical copies. Is it always a good thing for the DNA to be copied accurately? Why or why not?

Soapberry bugs are small relative to their host plants, and the bugs vary in their abilities to disperse. Although they have wings, many soapberry bugs have developed flight muscles and walk more often than they fly.

Why did early scientists call interphase the resting stage?

You are given two sample tubes, each containing a white powder: your task is to determine if these powders are pure substances and two samples of same substance. briefly describe your strategy for completing your task.

What have you learned about heredity and genetics that could support?

1. If the sequence on a DNA molecule was CCTAG, the complementary sequence on the mRNA would be: GGAUC GGUTC GGATC UUATU