根据下图所示实验，回答问题。 （1）实验A中观察到的现象是，说明相同条件下，C

生物生存所需要的基本条件有______、阳光、空气和水，还有适宜的______和一定的生存空间．

下列各句中，加点的词语使用恰当的一句是（）

A公司负责人表示：业务扩大的原因，主要是由于投资后公司周转资金充足。

B空间资源既是绝对无限的，又是相对有限的。就宇宙而言，空间是无限的；就这个意义讲，空间资源是无限的。

C缺乏艺术力量和文笔情趣，文学功能就未免会受到影响。

D经过他长期的研究、试验，终于出色地掌握了果树嫁接技术。

城市规划的意义( )。

A．在于它对城市发展的规范化和控制

B．在于它对城市发展的干预和控制

C．在于它对城市发展的规范化和干预

D．在于它对城市发展的指导和控制

有关甾体激素，以下哪些是错误的

A．由肝脏降解，经肾脏排泄
B．孕烯醇酮是合成所有甾体激素的前体物质
C．雌激素是由18个碳原子组成，孕激素由21个碳原子组成，雄激素是由19个碳原子组成
D．甾体激素属于类固醇激素
E．雌激素、孕激素、雄激素、前列腺素均属甾体激素

Melissa and LoveLetter made use of the trust that exists between friends or colleagues. Imagine receiving an (16) from a friend who asks you to open it. This is what happens with Melissa and several other similar email (17) . Upon running, such worms usually proceed to send themselves out to email addresses from the victim’s address book, previous emails, web pages (18) .
As administrators seek to block dangerous email attachments through the recognition of well-known (19) , virus writers use other extensions to circumvent such protection. Executable (.exe) files are renamed to .bat and .cmd plus a whole list of other extensions and will still run and successfully infect target users.
Frequently, hackers try to penetrate networks by sending an attachment that looks like a flash movie, which, while displaying some cute animation, simultaneously runs commands in the background to steal your passwords and give the (20) access to your network.

A．virtual

B．virus

C．worms

D．bacteria