(Q).
Q: What structures of the cardiovascular system help regulate body processes by either constricting or dilating? Read this paragraph and choose the correct option from the provided answers: Blood vessels help regulate body processes by either constricting (becoming narrower) or dilating (becoming wider). These actions occur in response to signals from the autonomic nervous system or the endocrine system. Constriction occurs when the muscular walls of blood vessels contract. This reduces the amount of blood that can flow through the vessels (see Figure below ). Dilation occurs when the walls relax. This increases blood flows through the vessels. Choices: - muscles - cartilage - capillaries - blood vessels A:
(A).
blood vessels

(Q).
Q: What bonds form because they give atoms a more stable arrangement of electrons? Read this paragraph and choose the correct option from the provided answers: Covalent bonds form because they give atoms a more stable arrangement of electrons. Look at the hydrogen atoms in Figure above . Alone, each hydrogen atom has just one electron. By sharing electrons with another hydrogen atom, it has two electrons: its own and the one in the other hydrogen atom. The shared electrons are attracted to both hydrogen nuclei. This force of attraction holds the two atoms together as a molecule of hydrogen. Choices: - Hydrogen bond - Ionic bond - Polar bond - covalent A:
(A).
covalent

(Q).
Q: What system transports minerals and water in a plant? Read this paragraph and choose the correct option from the provided answers: Roots absorb water and minerals and transport them to stems. They also anchor and support a plant, and store food. A root system consists of primary and secondary roots. Each root is made of dermal, ground, and vascular tissues. Roots grow in length and width from primary and secondary meristem. Choices: - leaves - stamen - flowers - roots A:
(A).
roots