Electricity: Circuits and their Components — Science STD 7 — Question

I once watched a part of marathon on a straight road stretch. I noticed that some people seemed to be running at the same speed during that distance while some people would speed up or slow down. How were their motion different?

Urinary bladder is the part of human excretory system. What is its role in excretion?

Is the process of respiration the same in all animals?

How can you test the presence of carbon dioxide?

State whether the bulb glows when the circuit is opened.

Do non-metals conduct electricity?

How do bird excrete waste?

Spores are covered by a hard covering. Give reasons.

Fill in the blanks in the following statement: When carbon dioxide is passed through lime water, it turns milky due to the formation of __________.