When people exercise, their body cells build up more waste quickly. which two body systems work together to remove these wastes from their cells? (1) immune and endocrine (3) respiratory and circulatory (2) digestive and skeletal (4) circulatory and digestive

Choose one animal (cheetas) and research on the internet what has contributed to this animal becoming "endangered" or "threatened." what animal you have chosen? how long has the animal been endangered or threatened? what has contributed to this animal’s endangered or threatened status? why is it important to save this animal from extinction? after researching and gathering facts, write a 350-word letter from the point of view of an animal rights' activist. be sure to include at least five facts that you learned from your research.

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Describe how viruses and bacteria can be used as biological weapons. what are some of the potential threats and potential benefits? do you agree with the use of viruses and bacteria as biological weapons? why or why not?