Doctors have fought infections with penicillin for over 50 years. Recently, penicillin has not worked as well as before. Which of the following explanations can account for this observation?

if water moves into a cell, and the cell swells, what term best describes the environment inside the cell?

Of the three species, Acer rubrum, Acer sucre, and Pseudotriton rubrum, which are more closely related? A. Acer rubrum and Acer sucre B. Acer rubrum and Pseudotriton rubrum C. Acer sucre and Pseudotriton rubrum D.

Which structure does meiosis occur (meiosis results in the formation of eggs) ?

What is the main hormone in the male reproductive system? a. estrogen b. progesterone c. testosterone

Evidence indicates that the most probable long-term effect of smoking marijuana is

One reason common names are not useful to biologists is that they ... A. are in Latin. B. can apply to more than one animal. C. are too long. D. require the use of a dichotomous key. what is the answer nd why?

A species of butterfly has alleles for wing color that are either blue or orange. When a blue butterfly and an orange butterfly mate, their offspring have wings that are both blue and orange. Explain the process through which wing color is expressed.

Low blood levels of oxygen can bring on? A. Sneezez B. Hiccups C. Coughs D. Sighs

How do human activities increase the occurrence of species extinction?

Describe Coriolis effect and explain why it affects ocean currents.